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Effect of Zeolite Topology and Reactor Configuration on the Direct Conversion of CO2 to Light Olefins and Aromatics

  • Adrian Ramirez
    Adrian Ramirez
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • , 
  • Abhishek Dutta Chowdhury
    Abhishek Dutta Chowdhury
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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    Orcidhttp://orcid.org/0000-0002-4121-7375
  • , 
  • Abhay Dokania
    Abhay Dokania
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • , 
  • Pieter Cnudde
    Pieter Cnudde
    Center for Molecular Modeling, Ghent University, Technologiepark 46, B-9052 Zwijnaarde, Belgium
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  • , 
  • Mustafa Caglayan
    Mustafa Caglayan
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • , 
  • Irina Yarulina
    Irina Yarulina
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • , 
  • Edy Abou-Hamad
    Edy Abou-Hamad
    Imaging and Characterization Core Laboratories, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • , 
  • Lieven Gevers
    Lieven Gevers
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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  • Samy Ould-Chikh
    Samy Ould-Chikh
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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    Orcidhttp://orcid.org/0000-0002-3486-0944
  • , 
  • Kristof De Wispelaere
    Kristof De Wispelaere
    Center for Molecular Modeling, Ghent University, Technologiepark 46, B-9052 Zwijnaarde, Belgium
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  • , 
  • Veronique van Speybroeck*
    Veronique van Speybroeck
    Center for Molecular Modeling, Ghent University, Technologiepark 46, B-9052 Zwijnaarde, Belgium
    *E-mail: [email protected]
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    Orcidhttp://orcid.org/0000-0003-2206-178X
  • , and 
  • Jorge Gascon*
    Jorge Gascon
    KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    *E-mail: [email protected]
    More by Jorge Gascon
    Orcidhttp://orcid.org/0000-0001-7558-7123
Cite this: ACS Catal. 2019, 9, 7, 6320–6334
Publication Date (Web):May 29, 2019
https://doi.org/10.1021/acscatal.9b01466

Copyright © 2019 American Chemical Society. This publication is licensed under these Terms of Use.

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Abstract

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The direct transformation of CO2 into high-value-added hydrocarbons (i.e., olefins and aromatics) has the potential to make a decisive impact in our society. However, despite the efforts of the scientific community, no direct synthetic route exists today to synthesize olefins and aromatics from CO2 with high productivities and low undesired CO selectivity. Herein, we report the combination of a series of catalysts comprising potassium superoxide doped iron oxide and a highly acidic zeolite (ZSM-5 and MOR) that directly convert CO2 to either light olefins (in MOR) or aromatics (in ZSM-5) with high space–time yields (STYC2-C4= = 11.4 mmol·g–1·h–1; STYAROM = 9.2 mmol·g–1·h–1) at CO selectivities as low as 12.8% and a CO2 conversion of 49.8% (reaction conditions: T = 375 °C, P = 30 bar, H2/CO2 = 3, and 5000 mL·g–1·h–1). Comprehensive solid-state nuclear magnetic resonance characterization of the zeolite component reveals that the key for the low CO selectivity is the formation of surface formate species on the zeolite framework. The remarkable difference in selectivity between the two zeolites is further rationalized by first-principles simulations, which show a difference in reactivity for crucial carbenium ion intermediates in MOR and ZSM-5.

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Introduction

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Today, more than 3 gigatons of CO2 are emitted to the atmosphere every month. (1) Undoubtedly, CO2 levels are higher than at any point in at least the past 800 000 years, leading to a dangerous temperature increase at the Earth’s surface. (2) In this scenario, methods to transform this greenhouse gas into valuable chemicals may help address (at least partially) this pressing challenge. (3) Indeed, the development of technologies that turn CO2 into valuable chemicals is gaining momentum in the scientific and industrial communities. (4,5)
One of the most promising approaches toward CO2 reductive valorization consists of the combination of conventional metallic catalysts with acidic zeolites. (6) This combination has been shown to enable the direct transformation of CO2 to chemicals with selectivities for either light olefins (C2–C4) or aromatics above the limitation of classical Fischer–Tropsch synthesis (FTS), as defined by the Anderson–Schulz–Flory (ASF) distribution. (7,8) In these bifunctional systems, the conversion of CO2 to hydrocarbons can proceed through two different routes: (i) the transformation of CO2 into CO via reverse water–gas shift (RWGS) and subsequent conversion of CO to hydrocarbons via the classical Fischer–Tropsch mechanism, (9) followed by hydrocarbon cracking, isomerization, aromatization, etc. on the zeolite; (10) (ii) the transformation of CO2 into methanol, (11) followed by its conversion into hydrocarbons over the zeolite framework via the classical methanol-to-hydrocarbons (MTH) mechanism. (12,13)
However, due to the lack of efficient catalysts for the first step (activation of CO2), productivities reported to date are low (see Table S1 for a complete overview of the state-of-the-art for CO2 conversion via bifunctional catalyst). In addition, multiple reactions are involved (oligomerization, cracking, dehydrogenation, cyclization, alkylation, isomerization, etc.), and many intermediates can serve as reactants in competitive reaction pathways, impeding the complete understanding of the global reaction mechanism. (14,15) Moreover, in most of the bifunctional systems reported, the selectivity to undesired CO represents more than half of the total products. (16−20) As direct consequence, many studies unfairly exclude the high CO selectivity when showing reaction data, thus reporting unrealistic catalyst CO free selectivities.
To overcome the limitations of the above materials, we have developed a novel catalyst combination comprising potassium superoxide-doped iron oxide and a highly acidic zeolite. The potassium superoxide-doped iron oxide stand-alone catalyst (Fe2O3@KO2) was recently reported by our group (21) and yields productivities in the order of commercial FTS materials. Here we go one step forward and combine this material with highly acidic zeolites to fine-tune the product distribution to either light olefins (C2–C4═) or aromatics. In particular, we have chosen ZSM-5 owing to the well-known ability of the MFI topology to generate aromatics (22) and mordenite (MOR) due to its ethylene shape selectivity within the 8-membered ring (8MR). (23,24) When the two components are placed together in a single reactor, high selectivities for either light olefins (via MOR) or aromatics (via ZSM-5) and high values of space–time yields with minimal selectivities for undesired CO and CH4 are achieved. In-depth characterization via magic angle spinning (MAS) solid-state nuclear magnetic resonance (ssNMR) spectroscopy on both spent zeolites reveals that the reaction mechanism is primarily driven by the incorporation of CO in the network in the form of surface formate species. Ab initio simulations further demonstrate a difference in stability of long-chain alkene intermediates on ZSM-5 and MOR. As carbenium ions are crucial intermediates for the conversion of hydrocarbons in zeolites, the different product distribution in the two zeolites can be attributed to the ability of these two zeolites to activate alkenes toward aromatics formation or cracking reactions.

Materials and Methods

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Chemicals

Iron oxide (Fe2O3, Aldrich), potassium superoxide (KO2, Aldrich), sodium aluminate (NaAlO2, Aldrich), tetrapropylammonium hydroxide (TPAOH, Aldrich), tetraethyl orthosilicate (TEOS, Aldrich), ammonium nitrate (NH4NO3, Aldrich), and ZSM-5 (SiO2/Al2O3 = 26, SiO2/Al2O3 = 52, SiO2/Al2O3 = 300, ACS Materials) were used as received. Mordenite (SiO2/Al2O3 = 20, Alfa Aesar) was calcined at 550 °C for 7 h prior to its use. ZSM-5 with SiO2/Al2O3 = 26 was always used unless otherwise stated.

Catalyst Preparation

The Fe2O3@KO2 catalyst was obtained by mortar mixing of Fe2O3 and KO2, keeping a molar ratio of Fe/K = 2. The resultant mixture was heated to 100 °C for 12 h prior to the catalytic measurements. ZSM-5 with SiO2/Al2O3 = 600 was synthesized in our laboratory by the following procedure: NaAlO2 (0.010 g), TPAOH (16.8 mL, 1 M in H2O), and TEOS (8.4 mL) were mixed in water (15.6 mL) and aged at 100 °C for 2 h. After being stirred overnight at room temperature, the mixture was transferred into an autoclave at 180 °C for 20 h for further crystallization. The collected solid was centrifuged and washed until pH 7 was reached. Following, the sample was calcined at 550 °C for 7 h. Due to the presence of Na ions on the zeolite, an ion-exchange step was applied with 1 M NH4NO3 solution. Afterward, the zeolite was again calcined at 550 °C for 7 h.

CO2 Hydrogenation Tests

Catalytic tests were executed in a 16-channel Flowrence platform from Avantium. Typically 50 mg of the stand-alone Fe2O3@KO2 catalyst and 100 mg of composite catalyst with Fe2O3@KO2/zeolite with mass ratio 1/1 in a dual-bed configuration were used. The mixed feed had 25 vol% of CO2 and 75 vol% of H2. In addition, 8 mL/min of He was mixed with the feed as internal standard. We aimed to have 10 000 mL·g–1·h–1 per channel in the stand-alone catalyst and 5000 mL·g–1·h–1 in the composite catalyst. The 16th channel was always left without catalyst as blank. The reaction temperature was typically set at 375 °C. Prior to feeding the reaction mixture, all samples were pre-treated in situ with a pure H2 atmosphere for 4 h at 350 °C. The tubes were then pressurized to 30 bar using a membrane-based pressure controller.
An Agilent 7890B gas chromatograph with two sample loops was used. After the loops were flushed for 24 min, the content was injected. One sample loop goes to a TCD channel with 2 Haysep pre-column and MS5A, where He, H2, CH4, and CO are separated. Gases that have longer retention times than CO2 on the Haysep column (Column 4 Haysep Q, 0.5 m, G3591-80023) are back-flushed. Further separation of permanent gases is done on another Haysep column (Column 5 Haysep Q, 6 ft, G3591-80013) to remove CO2 before going to MS5A. CO2 is sent to a channel with a restrictor to avoid CO2 on MS5A. Another sample loop goes to an Innowax pre-column (5 m, 0.20 mm o.d., 0.4 μm film). For the first 0.5 min of the method, the gases coming from the pre-column are sent to a Gaspro column (Gaspro 30 m, 0.32 mm o.d.) followed by a flame ionization detector (FID). After 0.5 min, the valve is switched, and the gases are sent to an Innowax column (45 m, 0.2 mm o.d., 0.4 μm) followed by a FID. The Gaspro column separates C1–C8, paraffins, and olefins. Innowax separates larger parafins and olefins (>C9), benzene/toluene/xylene (BTX), and C9+ aromatics.
Conversion (X, %), space–time yields (STY, mmol·g·cat–1·h–1), and selectivities (S, %) are defined as follows:
where CHe,blk, CHe,R, CCO2,blk, and CCO2,R are the concentrations determined by GC analysis of He in the blank (blk), He in the reactor (R) effluent, CO2 in the blank, and CO2 in the reactor effluent, respectively, CCn,R is the concentration of the reactor effluent determined by GC analysis of a product with n carbon atoms, and GHSVCO2 is the CO2 gas space–time velocity in mL·g·cat–1·h–1. The error in carbon balance was better than 2.5% in all cases.

Nitrogen Adsorption Measurements

Nitrogen adsorption and desorption isotherms were recorded on a Micromeritics ASAP 2040 system at 77 K. Samples were previously evacuated at 373 K for 16 h. The Brunauer–Emmett–Teller (BET) method was used to calculate the surface area. The p/p0 range for BET analysis was 0.067 < p/p0 < 0.249.

X-ray Diffraction (XRD) Measurements

XRD patterns were obtained using Bruker D8 equipment in Bragg–Brentano configuration using Cu Kα radiation. The diffractograms were scanned with a step size of 0.02° in the 2θ range of 20–80°. The crystalline phase was identified by comparison with data from the Inorganic Crystal Structure Database (ICSD).

Temperature-Programed Desorption (TPD) Measurements

TPD experiments were carried out on a Micromeritics ASAP 2020 analyzer. The catalyst samples were first heated in a helium flow at 350 °C for 4 h, followed by cooling to 50 °C. After cooling, the zeolites were saturated in ammonia, and the temperature of the samples was increased linearly at a rate of 10 K·min–1. Ammonia was fed at atmospheric pressure with a 5 vol% NH3 concentration diluted in helium. The ammonia desorption was continuously monitored by a thermal conductivity detector.

Inductively Coupled Plasma (ICP) Measurements

The analyses were carried out on an ICP–optical emission spectrometer after digestion of the solid samples. Complete digestion of the powder samples was achieved using aqua regia in a ratio of 1 mg of catalyst:1 mL of aqua regia for 24 h at room temperature.

Electron Microscopy and Elemental Mapping

Transmission electron microscopy (TEM) of the samples was performed with a Titan Themis-Z microscope from Thermo Fisher Scientific by operating it at an accelerating voltage of 300 kV and with a beam current of 0.5 nA. Dark-field imaging was performed by scanning TEM (STEM) coupled to a high-angle annular dark-field (HAADF) detector. The STEM-HAADF data were acquired with a convergence angle of 29.9 mrad and a HAADF inner angle of 30 mrad. Furthermore, an X-ray energy dispersive spectrometer (FEI SuperX, ∼0.7 srad collection angle) was also utilized in conjunction with DF-STEM imaging to acquire STEM-energy dispersive spectrometry (EDS) imaging data sets (image size 1024 × 1024 pixels, dwell time 5 μs). During the acquisition of these data sets, at every image pixel, a corresponding EDS spectrum was also acquired to generate simultaneously the elemental maps of Fe, O, C, and K atoms. It is also pertinent to note herein that spectrum-imaging data sets were acquired in so-called frame mode, in which the electron beam was allowed to dwell at each pixel for only a few microseconds in order to keep the total frame time to 6 s or less. Both imaging and spectroscopy data sets for each sample were acquired as well as analyzed with a newly developed software package called Velox from Thermo Fisher Scientific. The elemental maps for Fe, O, C, and K atoms were computed using the extracted intensities of their respective Kα lines after background subtraction. The generated maps were slightly post-filtered by applying a Gaussian filter (σ = 0.5).

Nuclear Magnetic Resonance Measurements

The MAS ssNMR spectroscopic experiments were performed on Bruker AVANCE III spectrometers operating at 400 MHz frequency for 1H using a conventional double-resonance 4 mm CPMAS probe (CP = cross-polarization). NMR chemical shifts are reported with respect to the external reference adamantane. For 1H–13C CP experiments, the following sequence was used: 90° pulse on the proton (pulse length 2.4 s), then a CP step with the contact time of typically 2 ms, and finally acquisition of the 13C NMR signal under high-power proton decoupling. The delay between the scans was set to 5 s to allow complete relaxation of the 1H nuclei, and the number of scans is mentioned in the respective figure captions. An exponential apodization function corresponding to a line broadening of 80 Hz was applied prior to Fourier transformation. The 2D 1H–13C heteronuclear correlation (HETCOR) ssNMR spectroscopy experiments were performed according to the following scheme: 90° proton pulse, t1 evolution period, CP to 13C, and detection of the 13C magnetization under two-pulse phase modulation (TPPM) decoupling. For the CP step, a ramped radio frequency (RF) field centered at 75 kHz was applied to the protons, while the 13C channel RF field was matched to obtain an optimal signal. Using a short contact time (0.2 ms) for the CP step, the polarization transfer in the dipolar correlation experiment was verified to be selective for the first coordination sphere to lead to correlations only between pairs of attached 1H–13C spins (C–H directly bonded). 2D 13C–13C spectra were recorded using a 2 s recycle delay as well as 10 ms (F2) and 6 ms (F1) acquisition times. Herein, carbons were polarized via CP, and 13C–13C mixing was achieved through proton-driven spin diffusion using phase-alternated recoupling irradiation schemes (PARIS) for 30 ms. 39K MAS ssNMR was performed on 900 MHz Bruker AVANCE IV 21.1 T spectrometers quipped with 4 mm CPMAS probes. 39K shifts were referenced to KBr, and typically a recycle delay of 1 s was used.

Computational Methodology

To rationalize the difference in selectivity between the two catalysts, a series of first-principles static and molecular dynamics (MD) simulations were performed in H-ZSM-5 and H-MOR according to general principles outlined in the work of V. Van Speybroeck et al. (25) All calculations were performed on fully periodic models of H-ZSM-5 and H-MOR. For H-ZSM-5, a single unit cell containing 96 T atoms has been used, while for H-MOR, a 1×1×2 super cell consisting of 96 T atoms has been used. Each catalyst model contains a single Brønsted acid site (BAS) per unit cell, which is created by substituting a Si atom by an Al atom and adding a charge-compensating proton. Both zeolites exhibit a fundamentally different channel system. H-ZSM-5 has the MFI topology, characterized by perpendicularly intersecting straight (5.3 Å × 5.6 Å) and sinusoidal (5.1 Å × 5.5 Å) 10-ring channels. (26) Al substitution was done at the T12 site, i.e., at the intersection of the straight and sinusoidal channels (Figure S1A). This location offers maximal accessibility for reacting guest molecules and is therefore the most common acid site position in modeling studies. (27) H-mordenite has the MOR topology, characterized by parallel 8-ring (2.6 Å × 5.7 Å) and 12-ring (6.5 Å × 7.0 Å) straight channels which are connected via 8-ring side pockets. (26) In H-MOR, the active site can be located at four different framework positions (Figure S1B) which result in different local environments for the adsorbates. The T1 site is situated at the intersection of the 12-ring channel and the 8-ring channel. This location provides a maximal amount of space for the adsorbed molecules, which can reside in the main 12-ring channel. The T2/T4 sites are located at the intersection of the 12-ring channel and the 8-ring side pocket, which provides partial confinement as adsorbates need to (partly) diffuse into the side pocket to approach this active site. The T3 site is found at the intersection of the 8-ring channel and the 8-ring side pocket. Bulky, long-chained molecules, however, are sterically hindered to diffuse into the 8-ring channel. Therefore, this active site will only be accessible for small molecules. In this study, the Al substitution is placed either at the T1 or T2 site, which will be further denoted as zeolite MOR-1 and MOR-2, respectively.
Periodic density functional theory (DFT) calculations were performed with the Vienna Ab Initio Simulation Package (VASP 5.4.1). (28−31) Optimized geometries were obtained using the conjugate gradient method. For all calculations, the PBE functional (32) with additional Grimme D3 dispersion corrections (33) was used. The projector augmented wave (PAW) approximation (34,35) was applied, and sampling of the Brillouin zone was restricted to the Γ-point. The plane wave energy cutoff was set to 600 eV. The threshold for the electronic self-consistent field (SCF) calculations was fixed at 10–5 eV. The nature of the stationary points was verified by a normal-mode analysis using partial Hessian vibrational analysis (PHVA) (36−38) on the adsorbates and an 8T cluster of the framework, centered around the acid site. To determine the adsorption enthalpy and free energy, thermal corrections were estimated based on the harmonic oscillator (HO) approximation with the in-house-developed processing toolkit TAMkin. (39)
Ab initio MD simulations were carried out with the CP2K software package (CP2K 3.0). (40) The revPBE functional (41) with inclusion of Grimme D3 dispersion corrections (33) was chosen as the level of theory. The DZVP-GTH basis set, (42) which is a combination of Gaussian basis functions and plane waves (43,44) with a cutoff energy of 320 Ry, was used for all atoms. The SCF convergence criterion was fixed at 10–6 eV. All simulations were performed in the NVT ensemble using a time step of 0.5 fs. The temperature (350 °C) was controlled by a chain of five Nosé–Hoover thermostats. (45,46) Unit cell parameters were determined from a preliminary 10 ps MD run in the NpT ensemble at 350 °C and 1 bar, which was controlled by an MTK barostat (see Table S2). (47) All systems were first equilibrated for 5 ps, followed by a production run of 100 ps to obtain a sufficient sampling of the phase space. The plane wave kinetic energy cutoff was set to 600 eV. The threshold for the electronic self-consistent cycle was set at 10–5 eV, while the ionic convergence criterion was set at 10–4 eV for all relaxations.
Umbrella sampling (US) simulations were performed with CP2K as MD engine, interfaced with the advanced simulation library PLUMED. (48) To sample the activated transition from an alkene to a carbenium ion, a predefined reaction coordinate or collective variable (CV) was used. The protonation of a linear alkene can be described by a single CV based on a coordination number (CN), which is defined as
in which the sum runs over two sets of atoms i and j with rij the interatomic distance between atom i and atom j, and r0 a reference distance. The parameters nn and nd are set at 6 and 12, respectively. To describe the proton transfer from the zeolite (z) to the hydrocarbon (hc), a CN between the oxygen atoms of the acid site (Oz) and the hydrogen atoms of the hydrocarbon (Hhc) (see Figure S2) is used as CV. (49) A reference distance of 1.25 Å was selected.
The CV was divided into 32 equidistant windows. For each window, a regular 25 ps MD simulation with an additional harmonic bias potential was carried out to ensure each part of the reaction is equally well sampled. (50) The bias potential has a spring constant of 3000 kJ·mol–1. The MD simulations were initiated from configurations that were randomly obtained from a moving bias potential simulation, describing the entire range of the reaction coordinate. For the US simulations, the TZVP-GTH basis was used, which allows for an improved description of the host–guest interactions. All other MD settings remained unchanged. Ultimately, the free energy profile was reconstructed from the sampling distribution in each window, using the weighted histogram analysis method (WHAM). (51,52)

Results

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Catalytic Performance of the Bifunctional Systems on the CO2 Hydrogenation Reaction

Synthesis of the stand-alone Fe-based catalyst was done according to our recent work. (21) Briefly, we prepared Fe2O3@KO2 catalyst by mortar mixing commercial iron oxide and commercial potassium superoxide, keeping a molar Fe/K ratio of 2. Figure 1A shows the XRD patterns of the commercial zeolites (MOR and ZSM-5) and the fresh and used stand-alone Fe2O3@KO2 after 50 h time-on-stream (TOS) at 375 °C, 30 bar, H2/CO2 = 3, and 10000 mL·g–1·h–1. In the fresh catalyst, a mixture of magnetite and potassium carbonate can be observed, while on the spent catalyst, no trace of the crystalline potassium carbonate is observed and the iron oxide is partially transformed to iron carbide, Fe5C2. STEM was used to further investigate the properties of the Fe2O3@KO2 catalyst after reaction. In accordance with our previous work, the Fe2O3@KO2 catalyst is composed mainly of a carbonaceous structure containing large amounts of cationic K (see Figure S3), homogeneously distributed over the matrix along with nanosized Fe (see Figure 1D). Both commercial zeolites were also characterized by means of ICP, BET, and ammonia TPD, showing values close to the ones provided by the manufacturer (see Figure S4 and Table S3).

Figure 1

Figure 1. Characterization of the bifunctional Fe2O3@KO2/zeolite material. (A) XRD patterns of the commercial zeolites and the fresh and spent stand-alone Fe catalyst. (B) TEM image of the stand-alone Fe catalyst activated under reaction conditions. K (C) and Fe (D) elemental mapping of the stand-alone Fe catalyst activated under reaction conditions.

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The detailed performance of the stand-alone Fe2O3@KO2 catalyst in the hydrogenation of CO2 after 50 h TOS at 375 °C, 30 bar, and H2/CO2 = 3 is summarized in Table S4. The CO2 conversion for this catalyst is 48.1%, with a total olefin selectivity of 57.4%, a CH4 selectivity of 15.2%, and a CO selectivity of only 15.9%. This catalytic performance is stable during at least 100 h TOS (see Figure S5). The light olefins fraction accounts for 49.3% of the total olefins, with a total olefin/paraffin ratio of 8.5. This product distribution is shifted drastically by assembling the bifunctional system incorporating a zeolite (MOR or ZSM-5) in a dual bed configuration with a 1/1 mass ratio. The addition of highly acidic ZSM-5 enhances the formation of aromatics (see Figure 2A). The selectivity of aromatics increases to 61.4% in the liquid fraction (C5+). However, this aromatic increase is accompanied by a decrease of the C2–C10 olefins and the formation of isobutane as main byproduct. The aromatic distribution is presented in Figure S6. We detected aromatics up to C10, toluene being the most abundant aromatic compound formed, followed by xylenes and C9 aromatics.

Figure 2

Figure 2. Catalytic performance of the bifunctional Fe2O3@KO2/zeolite system. (A) Product distribution of the Fe2O3@KO2/ZSM-5 and Fe2O3@KO2 catalysts after 50 h TOS. (B) Product distribution of the Fe2O3@KO2/MOR and Fe2O3@KO2 catalysts after 50 h TOS. (C) Stability of the Fe2O3@KO2/ZSM-5 bifunctional catalyst during 150 h TOS. (D) Stability of the Fe2O3@KO2/MOR bifunctional catalyst during 150 h TOS. Reaction conditions: 375 °C, 30 bar, H2/CO2 = 3, and 5000 mL·g–1·h–1.

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In a similar but different manner, the addition of MOR shifts the product distribution by enhancing the formation of ethylene and propylene, the two most highly demanded olefins (see Figure 2B). In particular, total selectivities to ethylene and propylene of 11.5% and 12.5% can be achieved. Interestingly, MOR does not seem to be active in hydrocarbon cracking, since the yields of most hydrocarbon fractions (except for the above-mentioned C2 and C3 fractions) remain almost unchanged. Both bifunctional systems are stable under reaction conditions for at least 100 h (see Figure 2C,D). On an additional note, the CO2 conversion remains invariable for both MOR and ZSM-5 systems in comparison with the bare Fe2O3@KO2 catalyst and with good reproducibility between different batches (see Table S5).
In line with some previous reports, (53) CO selectivity decreases upon incorporation of a zeolite component. In particular, in the Fe2O3@KO2/MOR the CO selectivity is 13.7% while in the Fe2O3@KO2/ZSM-5 it is as low as 12.8%, the lowest values reported for this kind of systems (see Table S1). This effect was further evaluated by performing CO co-feeding experiments. The addition of CO to the feed significantly increases the conversion for both bifunctional systems (see Table 1), which indirectly indicates the existence of carbonylated reactive intermediates during the reaction. Furthermore, the addition of CO to the feed also increases selectivity to olefins and aromatics, achieving a total C2–C4 olefin selectivity of 38.3% with a carbon conversion of 57.9% in the Fe2O3@KO2/MOR catalyst and a total aromatic selectivity of 28.4% with a carbon conversion of 58.3% in the Fe2O3@KO2/ZSM-5 catalyst at 375 °C (see Table 1).
Table 1. Effect of CO Co-feeding on the Fe2O3@KO2/Zeolite Bifunctional Catalystsa
   selectivity (%)
catalystCO co-feedconvb (%)C1aromC2-C4=
Fe2O3@KO2/ZSM-5no48.913.924.912.1
Fe2O3@KO2/ ZSM-5yes58.419.528.411.1
Fe2O3@KO2/MORno48.314.52.633.3
Fe2O3@KO2/MORyes57.920.73.038.3
a

Reaction conditions: 30 bar, H2/(CO+CO2) = 3, CO/CO2 = 1, and 5000 mL·g–1·h–1.

b

Total carbon (CO + CO2) conversion.

The effect of the catalyst spatial arrangement was studied for both bifunctional systems (see Figure S7). When the spatial arrangement was changed from dual bed to a mortar-mixed system, the performance was inferior in both systems, yielding carbon monoxide as the primary product. These results suggest that the acidity of the zeolite is poisoning the K basicity of the catalyst and vice versa, in accordance with previous reports. (8) It also suggests the high mobility of K in our catalytic system, which could indeed be rationalized by ssNMR spectroscopy. (21) In addition, for the particular system of ZSM-5, the effect of the SiO2/Al2O3 ratio was also evaluated. Figure 3A shows that, upon increasing the SiO2/Al2O3 ratio, the total aromatic selectivity decreases. Interestingly, a linear relationship was observed between the aromatics produced and the paraffins formed as byproducts, with isobutane as the main co-product in all cases (see Figure 3B). This trend is line with previous works, with isobutane being the main byproduct of the ethylene/propylene/butene aromatization, closely followed by propane. (14) H-transfer reactions, which play a key role in the formation of both aromatics and paraffins from light olefins, are the main driving force behind this effect. (54)

Figure 3

Figure 3. Effect of zeolite properties on the catalytic performance of the Fe2O3@KO2/ZSM-5 bifunctional system. (A) Effect of the SiO2/Al2O3 ratio on the aromatic selectivity. (B) Molar relationship between aromatics and the paraffins produced for the different SiO2/Al2O3 ratios tested. Reaction conditions: 375 °C, 30 bar, H2/CO2 = 3, 5000 mL·g–1·h–1, and 50 h TOS.

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The effect of the reaction conditions was further evaluated by performing CO2 hydrogenation tests at different reaction temperatures (325, 350, and 375 °C) and pressures (20, 30, and 40 bar). For the Fe2O3@KO2/ZSM-5 combination, it can be observed that reaction temperatures of 325 °C are not enough to completely trigger the aromatization mechanism in ZSM-5. On the other hand, similar aromatics selectivities are obtained at 350 and 375 °C (see Figure S8). Varying the pressure had less effect on the aromatics selectivity while, not surprisingly, increasing the pressure led to higher CO2 conversions (up to 53.8%) and vice versa. For the Fe2O3@KO2/MOR system (see Figure S9), an increase of the olefin selectivity with the pressure is observed, regardless of the reaction temperature, achieving a total C2–C4 light olefins selectivity of 35.2% with a CO2 conversion of 54.1% at 375 °C and 40 bar. In addition, unlike the case with ZSM-5, 325 °C seems to be sufficient to trigger the light olefin formation mechanism in this MOR system.

Solid-State NMR Characterization of the Spent Zeolites

To obtain some insight into the reaction mechanisms and derive structural information on zeolite-trapped species, advanced MAS ssNMR was performed on the post-reacted zeolite materials. In the 1D 1H–13C CP spectra (Figure S10), two predominant features were observed: (i) 8–40 ppm aliphatic and methyl groups and (ii) 120–158 ppm olefinic and/or aromatic moieties. On a closer look, the lack of signal for the unsaturated species specifically on the post-reacted MOR sample indicates the plausible non-existence of aromatic species. Alternatively, a relatively more intense signal on the post-reacted zeolite ZSM-5 (even with the lower number of scans) over zeolite MOR suggests relatively more efficient CP transfer in the former case, implying it is a relatively more hydrogen-rich system (Figure S10). Thermogravimetric analysis further confirms the existence of a hydrogen-deficient system in the MOR (Figure S11), as low hydrogen-to-carbon ratio coke (i.e., removed at temperatures above 550 °C) accounts for a total 12.7% weight loss in the spent MOR compared with the 4.5% observed in the spent ZSM-5. Next, 2D 1H–13C CP-HETCOR experiments were performed for 1H–13C correlations on both post-reacted zeolites (Figures 4 and 5), which clearly distinguishes their non-identical nature.

Figure 4

Figure 4. 2D MAS 1H–13C cross-polarization HETCOR ssNMR correlations of identified zeolite MOR trapped molecular scaffolds: olefinic/vinylic (in light green), aliphatic (in blue), and carbonyl (in purple). (A) Spectra obtained on the post-reacted MOR after the hydrogenation of carbon dioxide over Fe2O3@KO2/MOR for 50 h. Herein, dipolar cross-polarization was used to polarize carbons in this correlation spectrum. Zooms of (B) aliphatic and (C) carbonyl regions are displayed separately (number of scans = 3504).

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Figure 5

Figure 5. 2D MAS 1H–13C cross-polarization HETCOR ssNMR correlations. (A) Spectra obtained on the post-reacted ZSM-5 after the hydrogenation of carbon dioxide over Fe2O3@KO2/ZSM-5 for 50 h. (B) Identified zeolite ZSM-5-trapped molecular scaffolds: olefinic/vinylic (in light green), mono-aromatics (in green), poly-aromatics (in brown), and aliphatic (in blue) (number of scans = 2496).

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In MOR, olefinic carbons were typically correlated to both olefinic and aliphatic methyl hydrogens, which indicates that alkylated olefinic/vinylic species were the primary trapped organics (Figure 4). In the carbonyl region, two carbon signals at 189.8 and 192.8 ppm (typically a ketonic carbonyl region) correlate with a H-signal around 9.5–12 ppm, which could be attributed to surface formate species (Figure 4). These two signals presumably could appear due to the existence of surface formate species in a non-identical environment, such as in 8- and 12-membered rings within MOR.
Similarly, in the 2D 1H–13C CP-HETCOR spectra on ZSM-5, alkylated aromatics/poly-aromatics and olefinic/vinylic species, as well as paraffins, were distinguishable (Figure 5). Herein, we also identified that signals were relatively sharper/narrower in MOR than ZSM-5, which either could be due to the mobility of zeolite-trapped species or because they may reside in one exclusive conformation/environment in the zeolite framework. (55−58)
Although the NMR samples were prepared using naturally abundant reactants, we still have attempted to perform 2D 13C–13C correlation spectroscopy, only on the post-reacted ZSM-5 material (i.e., a more hydrogen efficient system than MOR), with an aim to investigate the heterogeneity of the sample as well as the zeolite-trapped C1 species (Figure S12A,B). In general, this measurement also reveals the existence of the alkylated aromatic/polyaromatic/olefinic species (Figure S12A), which is consistent with our other observations. Moreover, 2D 13C–13C spectra between 48 and 68 ppm illuminated the presence of several (albeit lower quantity) zeolite-surface bound oxygenated species (Figure S12B). In this region, two binding modes each of methanol and dimethyl ether on zeolite were identified. (56,57) The assignment of surface-adsorbed methanol species was further confirmed by a separate chemisorption experiment (Figure S12C). The line width of the 57 ppm peak (belonging to surface methoxy species, SMS) is only significantly broader, suggesting heterogeneity in its molecular environment. (58) Interestingly, another strong cross-peak between 57.1 and 47.1 ppm indicates the close proximity of SMS and surface-adsorbed methanol. (57) In principle, such close proximity is indicative of their reaction through the polarization of the C–H bond of SMS by a neighboring adjacent oxygen to form direct carbon–carbon bonds, possibly through the carbene-like reaction intermediate. (57) Additionally, as also indicated above, we have detected the migration of potassium as a hydrated potassium species (i.e., K(H2O)8+) formed in situ by high-field 39K ssNMR spectroscopy from the metallic to the zeolitic component during the reaction (see Figure S13). (59)

Theoretical Calculations on the Role of the Zeolite Framework

To obtain nanoscopic insight into the adsorption, mobility, and reactivity of alkene intermediates in ZSM-5 and MOR, a comprehensive set of theoretical calculations has been undertaken on C9 alkenes. We investigated 1-nonene as a model component because the C9 fraction appears to be unreactive on MOR, while it is almost entirely converted into aromatics on ZSM-5 (see Figure 2). Furthermore, a great fraction of the aromatics produced contain nine carbons (see Figure S6) and were also detected trapped in the ZSM-5 framework (see Figure S12A). This C9 aromatics fraction is likely formed via direct cyclization of adsorbed nonene that typically takes place through carbenium ion intermediates. (27,60−65) Additionally, as double bond isomerizations are known to readily occur, (66−68) the other n-nonene compounds are also included in this study.
Upon adsorption of an alkene in a Brønsted acid zeolite, four different adsorption states can be formed, as shown in Figure S14: (i) a physisorbed van der Waals (vdW) complex, characterized only by dispersion interactions with the zeolite wall; (ii) a physisorbed π-complex, in which the double C═C bond forms a π-H interaction with the Brønsted acid site; (iii) a chemisorbed carbenium ion, formed via protonation of the alkene; and (iv) a chemisorbed alkoxide, which is covalently bonded to the framework. Previously, we showed that alkoxides are unstable for C4–C8 alkenes at elevated temperature, (69,70) an observation which can likely be extrapolated to C9 alkoxides.
First, the adsorption behavior of linear nonene species was characterized by static DFT calculations. The resulting adsorption free energies at 350 °C for the n-nonene π-complexes and 2-nonyl carbenium ion in both zeolites are plotted in Figure 6. The adsorption enthalpies are shown in Figure S15. In MFI, the adsorbates are located in the straight 10-ring channel. In MOR-1—with the acid site located at the T1 position—the adsorbates are located in the main 12-ring channel. In MOR-2—with the acid site located at the T2 position—the adsorbates are located in the side pocket with the tail of the alkyl chain protruding in the main channel. Figure S16 shows the geometries of the optimized 1-nonene and 4-nonene π-complexes in both zeolites. In MFI, the adsorption free energies are found to be ca. 20–30 kJ·mol–1 lower than in MOR, which may be explained by the enhanced stabilization of the alkenes in the more confined 10-ring channels of MFI. The homologous n-nonene series has nearly equal adsorption free energies in MOR-1. However, in MOR-2, the adsorption free energy increases significantly from 1-nonene to 4-nonene. For 1-nonene only the double bond is situated in the side pocket, while for 4-nonene the alkyl chain penetrates much deeper into the 8-ring side pocket, thus resulting in an entropically less favorable configuration.

Figure 6

Figure 6. Adsorption free energy at 350 °C for 1-, 2-, 3-, and 4-nonene and 2-nonyl carbenium ion in H-ZSM-5, H-MOR-1, and H-MOR-2 with the empty framework and the respective n-nonene in the gas phase as reference state. For the carbenium ion, gas-phase 1-nonene and the empty framework are chosen as reference (level of theory: PBE-D3).

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The 2-nonyl carbenium ion has a much lower adsorption strength than the nonene π-complex in both zeolites. The free energy difference between 1-nonene and the 2-nonyl carbenium ion is higher in MOR-1 (49 kJ·mol–1) than in MFI (44 kJ·mol–1), although it should be noted that this rather subtle difference lies within the margin of error. In MOR-2, the chemisorbed carbocation could not be localized as a stable state on the potential energy surface. Due to the proximity of the acid site in the side pocket, the 2-nonyl carbenium ion spontaneously deprotonates during the geometry optimization. In general, secondary carbenium ions are not expected to be very stable based on static calculations, as was also shown in our earlier work. (49,69)
From these static simulations, we can already conclude that C9 alkenes generally adsorb more strongly in ZSM-5 compared to MOR. However, such static calculations show some limitations to properly account for the operating conditions. More particularly, only a single configuration of the adsorbate is considered, whereas at finite temperature, the adsorbed alkenes will typically possess sufficient energy to allow rapid rearrangements to other configurations. (49,69−72) To properly account for finite temperature effects and the configurational freedom of the guest species, MD simulations were performed at the reaction temperature of 350 °C.
The dynamic behavior of the C9 species inside ZSM-5, MOR-1, and MOR-2 was evaluated through five simulations, starting from 1-nonene, 2-nonene, 3-nonene, and 4-nonene π-complexes and a 2-nonyl carbenium ion geometry. Compared to those in smaller alkenes, nonyl carbenium ions may be formed more easily because the charge-stabilizing inductive effect is more pronounced for longer chains. (49) Indeed, alkene (de)protonation reactions can occur in the course of the simulations as well as regular transitions between the alkene π-complex and vdW-complex. To distinguish between the different adsorption states at each instant, an empirical criterion based on characteristic distances was established, as described in ref (69).
Figure 7 shows the sampled π-complex, vdW-complex, and carbenium ion time fractions during the 100 ps MD simulations. As the simulation length is probably too short to satisfy the ergodic hypothesis, these results should be considered as a qualitative description of the stability of these intermediates. Furthermore, the applied level of theory might also influence the relative lifetimes of the various species. In H-ZSM-5, the π-complex is the most sampled state, irrespective of the starting configuration, followed by the vdW-complex and the carbocation (Figure 7A). In H-MOR-1, the weaker π-H interactions are not strong enough to compensate for the entropic gain of forming vdW-complexes at 350 °C. As a result, the vdW-complex is by far the most stable state, despite the easy accessibility of the active site (Figure 7B). In H-MOR-2, the lifetime of the physisorbed states depends on the position of the nonene species. When (partly) residing in the 8MR side pocket, π-complexes are quite stable due to the proximity of the acid site and the hindered mobility of the alkyl chain. When they reside in the main channel, the situation resembles H-MOR-1, and vdW-complexes are the most stable state (Figure 7C). In general, the π-complex fraction has a higher probability to occur in ZSM-5 than in MOR, which suggests that nonene will bind more strongly to the acid site in ZSM-5 at 350 °C.

Figure 7

Figure 7. Sampling percentage of the π-complex, vdW-complex, and carbocation intermediates during the 100 ps MD simulations of the linear C9 species at 350 °C in (A) H-ZSM-5, (B) H-MOR-1, and (C) H-MOR-2 (level of theory: revPBE-D3/DZVP-GTH).

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To obtain further insight into the mobility of the nonene species in the zeolite pores in depth, 2D scatter plots of the mobility of 1-nonene and 4-nonene along the channel directions of MFI (Figure S17) and MOR (Figure S18) were constructed. In MOR-1, it is immediately clear that the alkene species can easily diffuse away from the active site along the large 12-ring main channel during the 100 ps simulation. In MOR-2, all nonene species diffuse rapidly from their initial position in the side pocket to the main channel, as this will result in a significant increase in conformational freedom. For 1-nonene the diffusion is almost instantaneous, while 4-nonene—which has a large part of the alkyl chain protruding in the side pocket—resides much longer in the side pocket before eventually traveling to the main channel, as evidenced by the large volume fraction of the side pocket which is visited during the simulation. The diffusion process to the main channel takes much longer, thus explaining the large π-complex fraction for the 3-nonene and 4-nonene simulations (Figure 7C). Also, 4-nonene and 3-nonene first undergo a spontaneous isomerization into 2-nonene before diffusing to the main channel, which confirms the higher adsorption strength of 2-nonene in MOR-2 as predicted by our static calculations (vide supra). On the other hand, in ZSM-5, the nonene species travel over a distance of only 10 Å along the straight channel. The C9 alkenes are more tightly bound in ZSM-5 and remain adsorbed at the channel intersection. The tail of the alkyl chain can reside both in the straight and in the sinusoidal channel. For 4-nonene, these two preferred adsorption locations can clearly be distinguished from the adsorbate mobility (see Figure S17B).
In ZSM-5, transitions between the neutral alkene and the carbenium ion are observed in four out of the five simulations (Figure 7A). The total sampling time of the carbocation state ranges between 0 and 10 ps. Although carbenium ions are clearly much less stable than physisorbed alkenes, their lifetime is not negligible. In contrast, in both MOR zeolites, carbenium ions were not sampled, except for a very brief instant (<0.1 ps) during the double bond isomerizations. Even when starting from a carbenium ion configuration, immediate deprotonations occurred. These observations indicate that the relative energy difference between a nonyl carbenium ion and a physisorbed nonene is larger for MOR than for ZSM-5. The varying pore topology of both zeolites may explain the difference in carbocation stability. The size of the zeolite pores was previously shown to crucially affect the stability of alkene intermediates. (73−79) The 10-ring channels of ZSM-5 provide a much better confinement than the larger 12-ring channels of MOR. Furthermore, the location of the acid site at the channel intersection allows for an optimal accessibility. In the main channel of MOR, the average distance of the adsorbate to the zeolite wall will be larger than in ZSM-5. Therefore, the stabilizing effect of dispersion and vdW interactions will be reduced. In the 8-ring side pocket of MOR, a much more confined space is available for the adsorbate. However, this beneficial effect is counteracted by the overall mobility and entropy loss when the adsorbate is located in the side pocket.
Based on this qualitative data set, it can be concluded that carbenium ions seem to be formed preferentially on ZSM-5. However, to estimate the reactivity toward double bond activation, US simulations were carried out to reconstruct the free energy profile for the protonation of 1-nonene into a nonyl carbenium ion. In this way, the configurational freedom of the adsorbed C9 species is equally well accounted for along the entire reaction coordinate. Figure S19 displays the resulting free energy profile for ZSM-5 and MOR-1 at 350 °C. Due to the tendency of nonene to diffuse along the main channel, zeolite MOR-2 was not considered. In ZSM-5, a free energy barrier of 61 kJ·mol–1 is obtained, while MOR-1 shows a protonation barrier of 67 kJ·mol–1. The free energy difference between 1-nonene and a nonyl carbenium ion amounts to 32 and 42 kJ·mol–1, respectively. Compared to the neutral alkene, carbenium ions are thus less stable in MOR than in ZSM-5 and their formation is slightly more highly activated. These free energy profiles clearly show the subtle difference between the two zeolites for the activation of 1-nonene.
The stability of carbenium ions is influenced not only by topology but, among others, also by temperature, chain length, and branching. (49,69) For higher reaction temperatures, it can be expected that the stability of carbenium ions will increase also in MOR. Furthermore, branching affects the stability of alkene intermediates to a large extent, since more stable tertiary carbenium ions may be formed upon protonation. Herein, we assumed that the importance of branched alkenes is limited, as linear α-olefins are the primary FTS products. However, the relevance of branched intermediates might be a topic for further investigation.

Discussion

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In line with previous reports, (7,8,16−20) our results confirm that the addition of a highly acidic zeolite to a CO2 hydrogenation catalyst shifts the product distribution, breaking now the ASF distribution. The addition of highly acidic ZSM-5 enhances the formation of aromatics (see Figure 2A), increasing the selectivity to 61.4% in the liquid fraction (C5+). However, this increase in aromatics is accompanied by a decrease of the C2–C10 olefins and the formation of isobutane as the main byproduct (see Figure 3B). The addition of MOR enhances the formation of ethylene and propylene (see Figure 2B), with a total selectivity to ethylene of 11.5% and a total selectivity to propylene of 12.5%. However, in this zeolite, the bulk of the hydrocarbon fraction remains practically unchanged. Interestingly, the CO selectivity decreases in both cases (as low as 12.8% in the ZSM-5 and 13.7% in the MOR), implying that CO plays a role in both zeolitic reaction networks. (54) Furthermore, when CO is co-fed in the system, the carbon conversion and both aromatic and light olefin selectivities sharply increase (Table 1).
The proximity of the two components of the bifunctional catalyst was found to be critical: when the spatial arrangement was changed from dual bed to mortar mixed, the main product was always CO for both MOR and ZSM-5 (see Figure S7). These results can be a consequence of K poisoning by the acidity of the zeolite. (8) The SiO2/Al2O3 ratio was also found to be critical for the ZSM-5 system: upon increasing the SiO2/Al2O3 ratio, the total aromatic selectivity decreased, showing a linear relationship between the aromatics produced and the paraffins formed as byproducts (see Figure 3B). According to our results, for each mole of aromatics produced, 0.9 mol of C3 paraffins and 1.5 mol of C4 paraffins are co-produced, regardless of the SiO2/Al2O3 ratio.
To unravel this complicated reaction network, advanced MAS ssNMR spectroscopy, including 2D correlation experiments (1H–13C and 13C–13C), was performed on the post-reacted zeolite materials to derive structural information on trapped organics. Altogether, our ssNMR study indicates that methylated olefinic/vinylic species, zeolite surface formate species, and paraffins were primarily trapped on the post-reacted MOR zeolite (Figure 4), whereas post-reacted zeolite ZSM-5 was overwhelmed by alkylated (i.e., both methylated and ethylated) aromatics, polyaromatics, and olefinic/vinylic species as well as paraffins (Figure 5 and Figure S12). The 2D 13C–13C spectrum also illuminates the presence of surface-adsorbed methanol and dimethyl ether, as well as surface methoxy species on the post-reacted zeolite ZSM-5 material. Therefore, the dominating reaction intermediates in the present case were characteristically similar to the hydrocarbon pool (HCP) species, like in the MTH process. (56)
By combining static DFT calculations and advanced MD simulations, the difference in adsorption behavior and reactivity of C9 alkene intermediates between ZSM-5 and MOR was clarified. The free energy profile for 1-nonene adsorption and protonation at 350 °C is schematically represented in Figure 8. The protonation barrier referenced to the empty framework and 1-nonene in the gas phase is 27 kJ·mol–1 higher in MOR than in ZSM-5. Compared to the gas-phase reactants, the nonyl carbenium ion is stabilized by 8 kJ·mol–1 in ZSM-5 and destabilized by 23 kJ·mol–1 in MOR. It should be stressed that the adsorption free energies were obtained from static calculations, whereas the activation free energies were obtained from MD simulations. As a result, the absolute quantitative values may be prone to some uncertainties. However, the overall data set illustrates the difference in carbenium ion stability for both zeolites. The reason for this reactivity difference is two-fold. First, 1-nonene adsorbs less strongly on MOR, which may be explained by the reduced confinement of the large 12MR zeolite channels compared to ZSM-5. Furthermore, it was discovered that nonene species tend to diffuse into the main channel in MOR, even when they were originally located in the side pocket. Second, the intrinsic activation barrier for the protonation of 1-nonene is slightly higher in H-MOR.

Figure 8

Figure 8. Free energy profile for the adsorption (from static calculations, level of theory: PBE-D3) and protonation (from umbrella sampling, level of theory: revPBE-D3/TZVP-GTH) of 1-nonene π-complex into 2-nonyl carbenium ion in H-ZSM-5 (blue) and H-MOR-1 (red) at 350 °C, with the empty framework and 1-nonene in gas phase as reference states.

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The different product distributions obtained from the two catalysts can (partly) be attributed to the ability of these zeolites to activate alkenes and form carbenium ions. Carbenium ions indeed play a crucial role in the further conversion of large olefins into either aromatics, light olefins, or alkanes. By properly choosing the zeolite topology, the stabilization of the involved intermediates can be influenced and the selectivity can be tuned toward the targeted product distribution. In ZSM-5, the 10-ring channels of ZSM-5 provide a much better confinement than the larger 12-ring channels of MOR, in agreement with earlier studies which showed the importance of the channel confinement in stabilizing small alkane intermediates. (80) In addition, ZSM-5 can more easily activate long alkenes to form carbenium ions that can further be incorporated into the aromatization cycle. On the other hand, in MOR the protonation barrier is higher and, as consequence, the bulk of the heavy olefin fraction remains practically unchanged (Figure 2B). Furthermore, since the accessible Brønsted acid sites of MOR may be blocked by K(H2O)8+ (Figure S13), it could not be expected to facilitate the aromatization of olefins, and indeed, no aromatics species were evidenced by ssNMR on MOR (unlike H-ZSM-5).
Based on the aforementioned results, a catalytic pathway for the Fe2O3@KO2/zeolite-catalyzed hydrogenation of CO2 to hydrocarbons is proposed in Figure 9. First, Fe2O3@KO2 catalyzes the RWGS reaction to produce CO and water from the reaction mixture (CO2 + H2) (Figure 9A). Next, part of the CO is transformed in the Fe nanoparticles to produce the whole range of hydrocarbons (see Table S4) while the remaining CO diffuses to the confined pores of both MOR and ZSM-5 zeolites to produce surface formate species, which are subsequently hydrogenated to form SMS in situ (20) (Figure 9B). This SMS species undergoes several transformations, yielding mostly ethylene. It is worth mentioning that the mechanism of formation of olefins directly from the surface carbonylated species has recently been elucidated, (55) which presumably goes through the formation of a ketene-based reaction intermediate during both MTH and syngas chemistry over zeolite. (81) Finally, the olefins produced on the Fe2O3@KO2 catalyst plus the ones resulting from the SMS species are further incorporated into the aromatization cycle. This cycle takes place exclusively on ZMS-5 and greatly depends on the acidity of the zeolite (Figure 3A). In addition, for each aromatic formed, paraffins are also produced, (14,54) with isobutane as the main byproduct (Figure 3B). Furthermore, the initial aromatics can undergo several transformations (i.e., transalkylation, isomerization), widening the final aromatic product distribution (Figure S6).

Figure 9

Figure 9. Proposed reaction pathways of the Fe2O3@KO2/zeolite-catalyzed hydrogenation of CO2 to light olefins and aromatics. (A) CO2 hydrogenation pathway on the stand-alone Fe2O3@KO2 catalyst. (B) CO incorporation pathway on MOR and ZMS-5. (C) Aromatization pathway on ZSM-5.

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Last but not least, the C2–C4 olefin STY of the Fe2O3@KO2/MOR composite and the aromatic STY of the Fe2O3@KO2/ZSM-5 composite reported here turns out to be the highest of those for the existing bifunctional systems (7,8,16−20,82−90) (see Figures S20 and S21 and Table S1). These elevated conversions can be attributed to the optimal performance of the Fe2O3@KO2 stand-alone catalyst (21) and the addition of the correct zeolite that enables the selectivity increase to either light olefins (MOR) or aromatics (ZSM-5).

Conclusions

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The combination in one single reactor of the appropriate Fe catalyst and zeolite topology results in the conversion of CO2 to olefins and aromatics with high selectivity and unprecedented values of productivity. Product distribution can be easily shifted to either light olefins (in case of MOR) or aromatics (in case of ZSM-5) by selecting the appropriate zeolite. Furthermore, the presence of a zeolite enables the conversion of undesired CO, boosting the total selectivity to the desired hydrocarbon fraction. Solid-state nuclear magnetic resonance characterization of the spent zeolites revealed that for both zeolites the reaction mechanism is driven by the incorporation of CO in the network in the form of surface formate. A combined static and dynamic set of DFT simulations showed a higher potential of ZSM-5 to activate long alkenes toward carbenium ions, in contrast to MOR where these fractions are nearly unreactive. This explains the higher selectivity of ZSM-5 toward formation of aromatics. Our findings could help unravel the reaction network in bifunctional systems with the ultimate goal of the mass adoption of non-fossil-fuel technologies for the production of hydrocarbons in the near future.

Supporting Information

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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acscatal.9b01466.

  • Comparison with state-of-the-art materials, additional computational calculations, characterization of catalysts, and complementary activity measurements, including Figures S1–S21 and Tables S1–S5 (PDF)

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Author Information

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  • Corresponding Authors
  • Authors
    • Adrian Ramirez - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Abhishek Dutta Chowdhury - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia;  Orcidhttp://orcid.org/0000-0002-4121-7375
    • Abhay Dokania - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Pieter Cnudde - Center for Molecular Modeling, Ghent University, Technologiepark 46, B-9052 Zwijnaarde, Belgium
    • Mustafa Caglayan - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Irina Yarulina - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Edy Abou-Hamad - Imaging and Characterization Core Laboratories, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Lieven Gevers - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
    • Samy Ould-Chikh - KAUST Catalysis Center (KCC), Advanced Catalytic Materials, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia;  Orcidhttp://orcid.org/0000-0002-3486-0944
    • Kristof De Wispelaere - Center for Molecular Modeling, Ghent University, Technologiepark 46, B-9052 Zwijnaarde, Belgium
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

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Funding for this work was provided by King Abdullah University of Science and Technology (KAUST). V.V.S. and P.C. acknowledge funding from the European Union’s Horizon 2020 research and innovation program (consolidator ERC grant agreement no. 647755-DYNPOR (2015–2020)). K.D.W. is a fellow funded by the FWO (FWO16-PDO-047). Dr. Vanduyfhuys is acknowledged for his contribution to constructing the mobility plots. The computational resources and services used were provided by Ghent University (Stevin Supercomputer Infrastructure), the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO).

References

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This article references 90 other publications.

  1. 1
    WMO. The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2016, Greenhouse Gas Bulletin (GHG Bulletin) No. 13; World Meteorological Organization, 2017.
    Google Scholar
    There is no corresponding record for this reference.
  2. 2
    Global Carbon Budget 2018. https://www.globalcarbonproject.org/carbonbudget (accessed May 25, 2019).
    Google Scholar
    There is no corresponding record for this reference.
  3. 3
    Alper, E.; Orhan, O. Y. CO2 utilization: Developments in conversion processes. Petroleum 2017, 3, 109– 126,  DOI: 10.1016/j.petlm.2016.11.003
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    There is no corresponding record for this reference.
  4. 4
    Álvarez, A.; Bansode, A.; Urakawa, A.; Bavykina, A. V.; Wezendonk, T. A.; Makkee, M.; Gascon, J.; Kapteijn, F. Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Catalyzed CO2 Hydrogenation Processes. Chem. Rev. 2017, 117, 9804– 9838,  DOI: 10.1021/acs.chemrev.6b00816
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    4
    Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Processes
    Alvarez, Andrea; Bansode, Atul; Urakawa, Atsushi; Bavykina, Anastasiya V.; Wezendonk, Tim A.; Makkee, Michiel; Gascon, Jorge; Kapteijn, Freek
    Chemical Reviews (Washington, DC, United States) (2017), 117 (14), 9804-9838CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. The recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to formate/formic acid, methanol, and di-Me ether are thoroughly reviewed, with special emphasis on thermodn. and catalyst design considerations. After introducing the main motivation for the development of such processes, we first summarize the most important aspects of CO2 capture and green routes to product H2. Once the scene in terms of feedstocks is introduced, we carefully summarize the state of the art in the development of heterogeneous catalysts for these important hydrogenation reactions. Finally, in an attempt to give an order of magnitude regarding CO2 valorization, we critically assess economical aspects of the prodn. of methanol and DME and outline future research and development directions.
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  5. 5
    Centi, G.; Quadrelli, E. A.; Perathoner, S. Catalysis for CO2 conversion: a key technology for rapid introduction of renewable energy in the value chain of chemical industries. Energy Environ. Sci. 2013, 6, 1711– 1731,  DOI: 10.1039/c3ee00056g
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    5
    Catalysis for CO2 conversion: a key technology for rapid introduction of renewable energy in the value chain of chemical industries
    Centi, Gabriele; Quadrelli, Elsje Alessandra; Perathoner, Siglinda
    Energy & Environmental Science (2013), 6 (6), 1711-1731CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)
    A review. Replacement of part of the fossil fuel consumption by renewable energy, in particular in the chem. industry, is a central strategy for resource and energy efficiency. This perspective will show that CO2 is the key mol. to proceed effectively in this direction. The routes, opportunities and barriers in increasing the share of renewable energy by using CO2 reaction and their impact on the chem. and energy value chains are discussed after introducing the general aspects of this topic evidencing the tight integration between the CO2 use and renewable energy insertion in the value chain of the process industry. The focus of this perspective article is on the catalytic aspects of the chemistries involved, with an anal. of the state-of-the-art, perspectives and targets to be developed. The reactions discussed are the prodn. of short-chain olefins (ethylene, propylene) from CO2, and the conversion of carbon dioxide to syngas, formic acid, methanol and di-Me ether, hydrocarbons via Fischer-Tropsch synthesis and methane. The relevance of availability, cost and environmental footprints of H2 prodn. routes using renewable energies is addressed. The final part discusses the possible scenario for CO2 as an intermediary for the incorporation of renewable energy in the process industry, with a concise road-map for catalysis needs and barriers to reach this goal.
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  6. 6
    Dokania, A.; Ramirez, A.; Bavykina, B.; Gascon, J. Heterogeneous Catalysis for the Valorization of CO2: Role of Bifunctional Processes in the Production of Chemicals. ACS Energy Lett. 2019, 4, 167– 179,  DOI: 10.1021/acsenergylett.8b01910
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    6
    Heterogeneous Catalysis for the Valorization of CO2: Role of Bifunctional Processes in the Production of Chemicals
    Dokania, Abhay; Ramirez, Adrian; Bavykina, Anastasiya; Gascon, Jorge
    ACS Energy Letters (2019), 4 (1), 167-176CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)
    A review is given. CO2 is an abundant C feedstock, and there exists a sustained interest in methods for its utilization. At the moment, several routes that rely on the use of renewable energy for the valorization of CO2 are being considered, with a strong emphasis on fully electrocatalytic routes. Here, we highlight the role that heterogeneous catalysis may play in hybrid processes in which H is obtained via electrolysis and CO2 is valorized in a 2nd, dark step. Targeting high selectivity to value-added products (olefins and aroms.), we cover CO2-to-chems. routes that involve cascade multifunctional processes. In doing so, we highlight the main advantages of this approach along with the most important challenges and remaining questions.
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  7. 7
    Gao, P.; Dang, S.; Li, S.; Bu, X.; Liu, Z.; Qiu, M.; Yang, C.; Wang, H.; Zhong, L.; Han, Y.; Liu, Q.; Wei, W.; Sun, Y. Direct Production of Lower Olefins from CO2 Conversion via Bifunctional Catalysis. ACS Catal. 2018, 8, 571– 578,  DOI: 10.1021/acscatal.7b02649
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    7
    Direct Production of Lower Olefins from CO2 Conversion via Bifunctional Catalysis
    Gao, Peng; Dang, Shanshan; Li, Shenggang; Bu, Xianni; Liu, Ziyu; Qiu, Minghuang; Yang, Chengguang; Wang, Hui; Zhong, Liangshu; Han, Yong; Liu, Qiang; Wei, Wei; Sun, Yuhan
    ACS Catalysis (2018), 8 (1), 571-578CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    Direct conversion of carbon dioxide (CO2) into lower olefins (C2=-C4=), generally referring to ethylene, propylene, and butylene, is highly attractive as a sustainable prodn. route for its great significance in greenhouse gas control and fossil fuel substitution, but such a route always tends to be low in selectivity toward olefins. Here we present a bifunctional catalysis process that offers C2=-C4= selectivity as high as 80% and C2-C4 selectivity around 93% at more than 35% CO2 conversion. This is achieved by a bifunctional catalyst composed of indium-zirconium composite oxide and SAPO-34 zeolite, which is responsible for CO2 activation and selective C-C coupling, resp. We demonstrate that both the precise control of oxygen vacancies on the oxide surface and the integration manner of the components are crucial in the direct prodn. of lower olefins from CO2 hydrogenation. No obvious deactivation is obsd. over 150 h, indicating a promising potential for industrial application.
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  8. 8
    Wei, J.; Ge, Q.; Yao, R.; Wen, Z.; Fang, C.; Guo, L.; Xu, H.; Sun, J. Directly converting CO2 into a gasoline fuel. Nat. Commun. 2017, 8, 15174,  DOI: 10.1038/ncomms15174
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    8
    Directly converting CO2 into a gasoline fuel
    Wei Jian; Ge Qingjie; Yao Ruwei; Wen Zhiyong; Fang Chuanyan; Guo Lisheng; Xu Hengyong; Sun Jian; Wei Jian; Yao Ruwei; Wen Zhiyong; Guo Lisheng
    Nature communications (2017), 8 (), 15174 ISSN:.
    The direct production of liquid fuels from CO2 hydrogenation has attracted enormous interest for its significant roles in mitigating CO2 emissions and reducing dependence on petrochemicals. Here we report a highly efficient, stable and multifunctional Na-Fe3O4/HZSM-5 catalyst, which can directly convert CO2 to gasoline-range (C5-C11) hydrocarbons with selectivity up to 78% of all hydrocarbons while only 4% methane at a CO2 conversion of 22% under industrial relevant conditions. It is achieved by a multifunctional catalyst providing three types of active sites (Fe3O4, Fe5C2 and acid sites), which cooperatively catalyse a tandem reaction. More significantly, the appropriate proximity of three types of active sites plays a crucial role in the successive and synergetic catalytic conversion of CO2 to gasoline. The multifunctional catalyst, exhibiting a remarkable stability for 1,000 h on stream, definitely has the potential to be a promising industrial catalyst for CO2 utilization to liquid fuels.
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  9. 9
    Ramirez, A.; Gevers, L.; Bavykina, A.; Ould-Chikh, S.; Gascon, J. Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins. ACS Catal. 2018, 8, 9174– 9182,  DOI: 10.1021/acscatal.8b02892
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    9
    Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins
    Ramirez, Adrian; Gevers, Lieven; Bavykina, Anastasiya; Ould-Chikh, Samy; Gascon, Jorge
    ACS Catalysis (2018), 8 (10), 9174-9182CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    We report the synthesis of a highly active, selective, and stable catalyst for the hydrogenation of CO2 to short chain olefins in one single step by using a metal org. framework as catalyst precursor. By studying the promotion of the resulting Fe(41 wt. %)-carbon composites with different elements (Cu, Mo, Li, Na, K, Mg, Ca, Zn, Ni, Co, Mn, Fe, Pt, and Rh), we have found that only K is able to enhance olefin selectivity. Further catalyst optimization in terms of promoter loading results in catalysts displaying unprecedented C2-C4 olefin space time yields of 33.6 mmol·gcat-1·h-1 at XCO2 = 40%, 320 °C, 30 bar, H2/CO2 = 3, and 24 000 mL·g-1·h-1. Extensive characterization demonstrates that K promotion affects catalytic performance by (i) promoting a good balance between the different Fe active phases playing a role in CO2 hydrogenation, namely, iron oxide and iron carbides and by (ii) increasing CO2 and CO uptake while decreasing H2 affinity, interactions responsible for boosting olefin selectivity.
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  10. 10
    Rahimi, N.; Karimzadeh, R. Catalytic Cracking of Hydrocarbons over Modified ZSM-5 Zeolites to Produce Light Olefins: A Review. Appl. Catal., A 2011, 398, 1– 17,  DOI: 10.1016/j.apcata.2011.03.009
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    10
    Catalytic cracking of hydrocarbons over modified ZSM-5 zeolites to produce light olefins: A review
    Rahimi, Nazi; Karimzadeh, Ramin
    Applied Catalysis, A: General (2011), 398 (1-2), 1-17CODEN: ACAGE4; ISSN:0926-860X. (Elsevier B.V.)
    A review. Steam cracking of hydrocarbons has been the major source of light olefins for more than half a century. The recent studies have reported that ethylene and propylene can also be produced through the cracking of hydrocarbons over modified ZSM-5 zeolites in a considerable amt. This paper highlights the important current ideas about acid-catalyzed hydrocarbon cracking that has resulted in high yield of ethylene and propylene. Light olefin prodn. via catalytic cracking of various industrial feedstocks, ranging from heavy hydrocarbons to ethane, over modified ZSM-5 zeolites, has been reviewed in the present paper. Furthermore, the influence of various employed promoters, i.e., alkali and alk. earth, transition, rare earth elements, and phosphorus, on the chem. properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed. Moreover, the influences of different factors, including the zeolite acidity, Si/Al ratio and the temp., on the light olefin prodn. and the reaction scheme have been specified. The role of incorporated element in the catalytic cracking mechanism is also summarized.
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  11. 11
    Jadhav, S. G.; Vaidya, P. D.; Bhanage, B. M.; Joshi, J. B. Catalytic Carbon Dioxide Hydrogenation to Methanol: A Review of Recent Studies. Chem. Eng. Res. Des. 2014, 92, 2557– 2567,  DOI: 10.1016/j.cherd.2014.03.005
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    11
    Catalytic carbon dioxide hydrogenation to methanol: A review of recent studies
    Jadhav, Suhas G.; Vaidya, Prakash D.; Bhanage, Bhalchandra M.; Joshi, Jyeshtharaj B.
    Chemical Engineering Research and Design (2014), 92 (11), 2557-2567CODEN: CERDEE; ISSN:1744-3563. (Elsevier B.V.)
    A review. Methanol demand was continuously increasing in the chem. and energy industries. It was com. produced from synthesis gas (CO + CO2 + H2) using CuO/ZnO/Al2O3 catalysts. Today, much effort was being put on the development of technologies for its prodn. from carbon dioxide (CO2). In this way, the Greenhouse effect might be mitigated. Over the years, several useful works on CO2 hydrogenation to methanol had been reported in the literature. In this article, we present a comprehensive overview of all the recent studies published during the past decade. Various aspects on this reaction system (such as thermodn. considerations, innovations in catalysts, influences of reaction variables, overall catalyst performance, reaction mechanism and kinetics, and recent technol. advances) were described in detail. The major challenges confronting methanol prodn. from CO2 were considered. By now, such a discussion was still missing, and we intend to close this gap in this paper.
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  12. 12
    Yarulina, I.; De Wispelaere, K.; Bailleul, S.; Goetze, J.; Radersma, M.; Abou-Hamad, E.; Vollmer, I.; Goesten, M.; Mezari, B.; Hensen, E. J. M.; Martínez-Espín, J. S.; Morten, M.; Mitchell, S.; Perez-Ramirez, J.; Olsbye, O.; Weckhuysen, B. M.; Van Speybroeck, V.; Kapteijn, F.; Gascon, J. Structure-Performance Descriptors and the Role of Lewis Acidity in the Methanol-to-Propylene Process. Nat. Chem. 2018, 10, 804– 812,  DOI: 10.1038/s41557-018-0081-0
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    12
    Structure-performance descriptors and the role of Lewis acidity in the methanol-to-propylene process
    Yarulina, Irina; De Wispelaere, Kristof; Bailleul, Simon; Goetze, Joris; Radersma, Mike; Abou-Hamad, Edy; Vollmer, Ina; Goesten, Maarten; Mezari, Brahim; Hensen, Emiel J. M.; Martinez-Espin, Juan S.; Morten, Magnus; Mitchell, Sharon; Perez-Ramirez, Javier; Olsbye, Unni; Weckhuysen, Bert M.; Van Speybroeck, Veronique; Kapteijn, Freek; Gascon, Jorge
    Nature Chemistry (2018), 10 (8), 804-812CODEN: NCAHBB; ISSN:1755-4330. (Nature Research)
    The combination of well-defined acid sites, shape-selective properties and outstanding stability places zeolites among the most practically relevant heterogeneous catalysts. The development of structure-performance descriptors for processes that they catalyze has been a matter of intense debate, both in industry and academia, and the direct conversion of methanol to olefins is a prototypical system in which various catalytic functions contribute to the overall performance. Propylene selectivity and resistance to coking are the two most important parameters in developing new methanol-to-olefin catalysts. Here, we present a systematic investigation on the effect of acidity on the performance of the zeolite 'ZSM-5' for the prodn. of propylene. Our results demonstrate that the isolation of Bronsted acid sites is key to the selective formation of propylene. Also, the introduction of Lewis acid sites prevents the formation of coke, hence drastically increasing catalyst lifetime.
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  13. 13
    Yarulina, I.; Dutta Chowdhury, A.; Meirer, F.; Weckhuysen, B. M.; Gascon, J. Recent Trends and Fundamental insights in the Methanol-to-Hydrocarbons Process. Nat. Catal. 2018, 1, 398– 411,  DOI: 10.1038/s41929-018-0078-5
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    13
    Recent trends and fundamental insights in the methanol-to-hydrocarbons process
    Yarulina, Irina; Chowdhury, Abhishek Dutta; Meirer, Florian; Weckhuysen, Bert M.; Gascon, Jorge
    Nature Catalysis (2018), 1 (6), 398-411CODEN: NCAACP; ISSN:2520-1158. (Nature Research)
    The prodn. of high-demand chem. commodities such as ethylene and propylene (methanol-to-olefins), hydrocarbons (methanol-to-hydrocarbons), gasoline (methanol-to-gasoline) and aroms. (methanol-to-aroms.) from methanol-obtainable from alternative feedstocks, such as carbon dioxide, biomass, waste or natural gas through the intermediate formation of synthesis gas-has been central to research in both academia and industry. Although discovered in the late 1970s, this catalytic technol. has only been industrially implemented over the past decade, with a no. of large com. plants already operating in Asia. However, as is the case for other technologies, industrial maturity is not synonymous with full understanding. For this reason, research is still intense and a no. of important discoveries have been reported over the last few years. In this review, we summarize the most recent advances in mechanistic understanding-including direct C-C bond formation during the induction period and the promotional effect of zeolite topol. and acidity on the alkene cycle-and correlate these insights to practical aspects in terms of catalyst design and engineering.
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  14. 14
    Batchu, R.; Galvita, V. V.; Alexopoulos, K.; Van der Borght, K.; Poelman, H.; Reyniers, M.-F.; Marin, G. B. Role of Intermediates in Reaction Pathways from Ethene to Hydrocarbons over H-ZSM-5. Appl. Catal., A 2017, 538, 207– 220,  DOI: 10.1016/j.apcata.2017.03.013
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    14
    Role of intermediates in reaction pathways from ethene to hydrocarbons over H-ZSM-5
    Batchu, Rakesh; Galvita, Vladimir V.; Alexopoulos, Konstantinos; Van der Borght, Kristof; Poelman, Hilde; Reyniers, Marie-Francoise; Marin, Guy B.
    Applied Catalysis, A: General (2017), 538 (), 207-220CODEN: ACAGE4; ISSN:0926-860X. (Elsevier B.V.)
    Insight in ethene to hydrocarbon transformation over a H-ZSM-5 catalyst was obtained by temporal anal. of (TAP) in the temp. range 598-698 K with pulses of higher olefins, dienes, cyclodienes and aroms. Pulses of propene, 1-butene and 1-hexene allowed to identify the cracking routes from ethene oligomerization products. When pulsing benzene or ethylbenzene, only accumulation of aroms. occurred. In-situ temp. programmed desorption (TPD) expts. after pulsing identified aroms. as long-lived surface species. The role of intermediates was assessed by pre-adsorption of the different feeds before pulsing ethene, in so-called pump-probe expts. Butene enhanced propene formation, while all other olefins favored butene prodn. via aliph. surface intermediates. The latter were also intermediates in the conversion of hexadiene to butene and aroms., while cyclohexadiene was converted to propene and aroms. via arom. surface intermediates. In contrast to ethylbenzene pulses alone, aroms. alkylation participated towards light olefin prodn. via sidechain/paring mechanisms. Isotope expts. of 13C2H4 over a catalyst cocked during continuous flow expts. with 12C only showed scrambling in both propene and butene products, stressing the role of long-lived arom. surface intermediates.
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  15. 15
    Guisnet, M.; Gnep, N. S. Mechanism of Short-Chain Alkane Transformation over Protonic Zeolites. Alkylation, Disproportionation and Aromatization. Appl. Catal., A 1996, 146, 33– 64,  DOI: 10.1016/0926-860X(96)00282-7
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    15
    Mechanism of short-chain alkane transformation over protonic zeolites. Alkylation, disproportionation and aromatization
    Guisnet, M.; Gnep, N. S.
    Applied Catalysis, A: General (1996), 146 (1), 33-64CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
    A review with 105 refs. on the mechanism of alkane activation on zeolites. The influence of pore structure and acidity of the protonic zeolites on their activity and selectivity is discussed.
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  16. 16
    Gao, J.; Jia, C.; Liu, B. Direct and Selective Hydrogenation of CO2 to Ethylene and Propene by Bifunctional Catalysts. Catal. Sci. Technol. 2017, 7, 5602– 5607,  DOI: 10.1039/C7CY01549F
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    16
    Direct and selective hydrogenation of CO2 to ethylene and propene by bifunctional catalysts
    Gao, Jiajian; Jia, Chunmiao; Liu, Bin
    Catalysis Science & Technology (2017), 7 (23), 5602-5607CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)
    Redn. of CO2 by H2 produced from renewable electricity on a large scale would benefit both carbon recycling as well as H2 storage and transport. Among the various CO2 hydrogenation reaction products, light olefins, such as ethylene and propylene, are very important intermediates in the chem. industry. However, very efficient catalytic systems that are able to drive CO2 hydrogenation reactions selectively to make olefins do not exist although the reactions are thermodynamically favorable. In this study, we demonstrated a selective hydrogenation process to directly convert CO2 to light olefins via a bifunctional catalyst composed of a methanol synthesis (In2O3/ZrO2) catalyst and a methanol-to-olefins (SAPO-34) catalyst. Under typical reaction conditions (e.g., 15 bar, 400 °C, and a space velocity of 12 L gcat-1 h-1), light olefins (ethylene and propylene) with a selectivity of 80-90% in hydrocarbons can be obtained with a CO2 conversion of ∼20%. To the best of our knowledge, this is the highest selectivity reported to date, which significantly surpasses the value obtained over conventional iron or cobalt CO2 Fischer-Tropsch synthesis catalysts (typically less than 50%). Moreover, our designed bifunctional catalyst shows good catalytic stability and can run for 50 h continuously without obvious activity decay. Our study provides an important contribution for CO2 conversion to value-added chems.
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  17. 17
    Liu, X.; Wang, M.; Zhou, C.; Zhou, W.; Cheng, K.; Kang, J.; Zhang, Q.; Deng, W.; Wang, Y. Selective Transformation of Carbon Dioxide into Lower Olefins with a Bifunctional Catalyst Composed of ZnGa2O4 and SAPO-34. Chem. Commun. 2018, 54, 140– 143,  DOI: 10.1039/C7CC08642C
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    17
    Selective transformation of carbon dioxide into lower olefins with a bifunctional catalyst composed of ZnGa2O4 and SAPO-34
    Liu, Xiaoliang; Wang, Mengheng; Zhou, Cheng; Zhou, Wei; Cheng, Kang; Kang, Jincan; Zhang, Qinghong; Deng, Weiping; Wang, Ye
    Chemical Communications (Cambridge, United Kingdom) (2018), 54 (2), 140-143CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    A bifunctional catalyst composed of ZnGa2O4 with a spinel structure and mol. sieve SAPO-34 catalyzes the direct conversion of CO2 to C2-C4 olefins with a selectivity of 86% and a CO2 conversion of 13% at 370°. The O vacancies on ZnGa2O4 surfaces are responsible for CO2 activation, forming a methanol intermediate, which is then converted into C2-C4 olefins in SAPO-34.
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  18. 18
    Li, Z.; Wang, J.; Qu, Y.; Liu, H.; Tang, C.; Miao, S.; Feng, Z.; An, H.; Li, C. Highly Selective Conversion of Carbon Dioxide to Lower Olefins. ACS Catal. 2017, 7, 8544– 8548,  DOI: 10.1021/acscatal.7b03251
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    18
    Highly Selective Conversion of Carbon Dioxide to Lower Olefins
    Li, Zelong; Wang, Jijie; Qu, Yuanzhi; Liu, Hailong; Tang, Chizhou; Miao, Shu; Feng, Zhaochi; An, Hongyu; Li, Can
    ACS Catalysis (2017), 7 (12), 8544-8548CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    Conversion of CO2 to value-added chems. has been a long-standing objective, and direct hydrogenation of CO2 to lower olefins is highly desirable but still challenging. Herein, we report a selective conversion of CO2 to lower olefins through CO2 hydrogenation over a ZnZrO/SAPO tandem catalyst fabricated with a ZnO-ZrO2 solid soln. and a Zn-modified SAPO-34 zeolite, which can achieve a selectivity for lower olefins as high as 80-90% among hydrocarbon products. This is realized on the basis of the dual functions of the tandem catalyst: hydrogenation of CO2 on the ZnO-ZrO2 solid soln. and lower olefins prodn. on the SAPO zeolite. The thermodn. and kinetic coupling between the tandem reactions enable the highly efficient conversion of CO2 to lower olefins. Furthermore, this catalyst is stable toward thermal and sulfur treatments, showing potential industrial application.
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  19. 19
    Dang, S.; Gao, P.; Liu, Z.; Chen, X.; Yang, C.; Wang, H.; Zhong, L.; Li, S.; Sun, Y. Role of Zirconium in Direct CO2 Hydrogenation to Lower Olefins on Oxide/Zeolite Bifunctional Catalysts. J. Catal. 2018, 364, 382– 393,  DOI: 10.1016/j.jcat.2018.06.010
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    19
    Role of zirconium in direct CO2 hydrogenation to lower olefins on oxide/zeolite bifunctional catalysts
    Dang, Shanshan; Gao, Peng; Liu, Ziyu; Chen, Xinqing; Yang, Chengguang; Wang, Hui; Zhong, Liangshu; Li, Shenggang; Sun, Yuhan
    Journal of Catalysis (2018), 364 (), 382-393CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    Direct prodn. of lower olefins (C=2-C=4: ethylene, propylene and butylene), basic carbon-based building blocks, from carbon dioxide (CO2) hydrogenation is highly attractive, although the selectivity towards olefins has been too low. Here we present a series of bifunctional catalysts contained indium-zirconium composite oxides with different In:Zr at. ratios and SAPO-34 zeolite, which can achieve a selectivity for C=2-C=4 as high as 65-80% and that for C2-C4 of 96% with only about 2.5% methane among the hydrocarbon products at CO2 conversion of 15-27%. The selectivity of CO via the reverse water gas shift reaction is lower than 70%. The product distribution is completely different from that obtained via CO2-based Fischer-Tropsch synthesis and deviates greatly from the classical Anderson-Schulz-Flory distribution. The zirconium component plays a crit. role in detg. the physicochem. properties and catalytic performance of bifunctional catalysts. Catalyst characterization and d. functional theory calcns. demonstrate that the incorporation of a certain amt. of zirconium can create more oxygen vacancy sites, stabilize the intermediates in CO2 hydrogenation and prevent the sintering of the active nanoparticles, thus leading to significantly enhanced catalytic activity, selectivity of hydrocarbons and stability for direct CO2 hydrogenation to lower olefins at the relatively high reaction temp. of 380 °C.
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  20. 20
    Ni, Y.; Chen, Z.; Fu, Y.; Liu, Y.; Zhu, W.; Liu, Z. Selective Conversion of CO2 and H2 into Aromatics. Nat. Commun. 2018, 9, 3457,  DOI: 10.1038/s41467-018-05880-4
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    20
    Selective conversion of CO2 and H2 into aromatics
    Ni Youming; Chen Zhiyang; Fu Yi; Liu Yong; Zhu Wenliang; Liu Zhongmin; Ni Youming; Chen Zhiyang; Fu Yi; Liu Yong; Zhu Wenliang; Liu Zhongmin; Chen Zhiyang; Fu Yi
    Nature communications (2018), 9 (1), 3457 ISSN:.
    Transformation of greenhouse gas CO2 and renewable H2 into fuels and commodity chemicals is recognized as a promising route to store fluctuating renewable energy. Although several C1 chemicals, olefins, and gasoline have been successfully synthesized by CO2 hydrogenation, selective conversion of CO2 and H2 into aromatics is still challenging due to the high unsaturation degree and complex structures of aromatics. Here we report a composite catalyst of ZnAlOx and H-ZSM-5 which yields high aromatics selectivity (73.9%) with extremely low CH4 selectivity (0.4%) among the carbon products without CO. Methanol and dimethyl ether, which are synthesized by hydrogenation of formate species formed on ZnAlOx surface, are transmitted to H-ZSM-5 and subsequently converted into olefins and finally aromatics. Furthermore, 58.1% p-xylene in xylenes is achieved over the composite catalyst containing Si-H-ZSM-5. ZnAlOx&H-ZSM-5 suggests a promising application in manufacturing aromatics from CO2 and H2.
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  21. 21
    Ramirez, A.; Ould-Chikh, S.; Gevers, L.; Dutta Chowdhury, A.; Abou-hamad, E.; Aguilar-Tapia, A.; Hazemann, J.; Wehbe, N.; Al Abdulghani, A. J.; Kozlov, S. M.; Cavallo, L.; Gascon, J. Tandem Conversion of CO2 to Valuable Hydrocarbons in Highly Concentrated Potassium Iron Catalysts. ChemCatChem 2019,  DOI: 10.1002/cctc.201900762
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    There is no corresponding record for this reference.
  22. 22
    Ono, Y. Transformation of Lower Alkanes into Aromatic Hydrocarbons over ZSM-5 Zeolites. Catal. Rev.: Sci. Eng. 1992, 34, 179– 226,  DOI: 10.1080/01614949208020306
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    22
    Transformation of lower alkanes into aromatic hydrocarbons over ZSM-5 zeolites
    Ono, Yoshio
    Catalysis Reviews - Science and Engineering (1992), 34 (3), 179-226CODEN: CRSEC9; ISSN:0161-4940.
    A review, with 76 refs., of the aromatization of C2-6-alkanes on ZSM-5 zeolites contg. Ga or Zn. Emphasis is placed on the reaction mechanism, the role of the metal cations, and the activation of the starting alkanes.
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  23. 23
    Jiao, F.; Pan, X.; Gong, K.; Chen, Y.; Li, G.; Bao, X. Shape-Selective Zeolites Promote Ethylene Formation from Syngas via a Ketene Intermediate. Angew. Chem., Int. Ed. 2018, 57, 4692,  DOI: 10.1002/anie.201801397
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    23
    Shape-Selective Zeolites Promote Ethylene Formation from Syngas via a Ketene Intermediate
    Jiao, Feng; Pan, Xiulian; Gong, Ke; Chen, Yuxiang; Li, Gen; Bao, Xinhe
    Angewandte Chemie, International Edition (2018), 57 (17), 4692-4696CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Syngas conversion by Fischer-Tropsch synthesis (FTS) is characterized by a wide distribution of hydrocarbon products ranging from one to a few carbon atoms. Reported here is that the product selectivity is effectively steered toward ethylene by employing the oxide-zeolite (OX-ZEO) catalyst concept with ZnCrOx-mordenite (MOR). The selectivity of ethylene alone reaches as high as 73 % among other hydrocarbons at a 26 % CO conversion. This selectivity is significantly higher than those obtained in any other direct syngas conversion or the multistep process methanol-to-olefin conversion. This highly selective pathway is realized over the catalytic sites within the 8-membered ring (8MR) side pockets of MOR via a ketene intermediate rather than methanol in the 8MR or 12MR channels. This study provides substantive evidence for a new type of syngas chem. with ketene as the key reaction intermediate and enables extraordinary ethylene selectivity within the OX-ZEO catalyst framework.
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  24. 24
    Jiao, F.; Li, J.; Pan, X.; Xiao, J.; Li, H.; Ma, H.; Wei, M.; Pan, Y.; Zhou, Z.; Li, M.; Miao, S.; Li, J.; Zhu, Y.; Xiao, D.; He, T.; Yang, J.; Qi, F.; Fu, Q.; Bao, X. Selective conversion of syngas to light olefins. Science 2016, 351, 1065– 1068,  DOI: 10.1126/science.aaf1835
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    24
    Selective conversion of syngas to light olefins
    Jiao, Feng; Li, Jinjing; Pan, Xiulian; Xiao, Jianping; Li, Haobo; Ma, Hao; Wei, Mingming; Pan, Yang; Zhou, Zhongyue; Li, Mingrun; Miao, Shu; Li, Jian; Zhu, Yifeng; Xiao, Dong; He, Ting; Yang, Junhao; Qi, Fei; Fu, Qiang; Bao, Xinhe
    Science (Washington, DC, United States) (2016), 351 (6277), 1065-1068CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
    Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C2=-C4=) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theor. limit of only 58% for C2-C4 hydrocarbons. We present a process that reaches C2=-C4= selectivity as high as 80% and C2-C4 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H2, and C-C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is obsd. within 110 h. Furthermore, this composite catalyst and the process may allow use of coal- and biomass-derived syngas with a low H2/CO ratio.
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  25. 25
    Van Speybroeck, V.; De Wispelaere, K.; Van der Mynsbrugge, J.; Vandichel, M.; Hemelsoet, K.; Waroquier, M. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev. 2014, 43, 7326– 7357,  DOI: 10.1039/C4CS00146J
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    25
    First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study
    Van Speybroeck, Veronique; De Wispelaere, Kristof; Van der Mynsbrugge, Jeroen; Vandichel, Matthias; Hemelsoet, Karen; Waroquier, Michel
    Chemical Society Reviews (2014), 43 (21), 7326-7357CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    To optimally design next generation catalysts a thorough understanding of the chem. phenomena at the mol. scale is a prerequisite. Apart from qual. knowledge on the reaction mechanism, it is also essential to be able to predict accurate rate consts. Mol. modeling has become a ubiquitous tool within the field of heterogeneous catalysis. Herein, we review current computational procedures to det. chem. kinetics from first principles, thus by using no exptl. input and by modeling the catalyst and reacting species at the mol. level. Therefore, we use the methanol-to-olefin (MTO) process as a case study to illustrate the various theor. concepts. This process is a showcase example where rational design of the catalyst was for a long time performed on the basis of trial and error, due to insufficient knowledge of the mechanism. For theoreticians the MTO process is particularly challenging as the catalyst has an inherent supramol. nature, for which not only the Bronsted acidic site is important but also org. species, trapped in the zeolite pores, must be essentially present during active catalyst operation. All these aspects give rise to specific challenges for theor. modeling. It is shown that present computational techniques have matured to a level where accurate enthalpy barriers and rate consts. can be predicted for reactions occurring at a single active site. The comparison with exptl. data such as apparent kinetic data for well-defined elementary reactions has become feasible as current computational techniques also allow predicting adsorption enthalpies with reasonable accuracy. Real catalysts are truly heterogeneous in a space- and time-like manner. Future theory developments should focus on extending our view towards phenomena occurring at longer length and time scales and integrating information from various scales towards a unified understanding of the catalyst. Within this respect mol. dynamics methods complemented with addnl. techniques to simulate rare events are now gradually making their entrance within zeolite catalysis. Recent applications have already given a flavor of the benefit of such techniques to simulate chem. reactions in complex mol. environments.
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  26. 26
    International Zeolite Association Home Page, http:www.iza-online.org (accessed May 25, 2019).
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  27. 27
    Van Speybroeck, V.; Hemelsoet, K.; Joos, L.; Waroquier, M.; Bell, R. G.; Catlow, C. R. A. Advances in theory their application within the field of zeolite chemistry. Chem. Soc. Rev. 2015, 44, 7044– 7111,  DOI: 10.1039/C5CS00029G
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    27
    Advances in theory and their application within the field of zeolite chemistry
    Van Speybroeck, Veronique; Hemelsoet, Karen; Joos, Lennart; Waroquier, Michel; Bell, Robert G.; Catlow, C. Richard A.
    Chemical Society Reviews (2015), 44 (20), 7044-7111CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    A review. Zeolites are versatile and fascinating materials which are vital for a wide range of industries, due to their unique structural and chem. properties, which are the basis of applications in gas sepn., ion exchange and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functionalities to obtain the best material for a given application. Over the last decades, theor. modeling has matured to a level that model guided design has become within reach. Major hurdles have been overcome to reach this point and almost all contemporary methods in computational materials chem. are actively used in the field of modeling zeolite chem. and applications. Integration of complementary modeling approaches is necessary to obtain reliable predictions and rationalizations from theory. A close synergy between experimentalists and theoreticians has led to a deep understanding of the complexity of the system at hand, but also allowed the identification of shortcomings in current theor. approaches. Inspired by the importance of zeolite characterization which can now be performed at the single atom and single mol. level from expt., computational spectroscopy has grown in importance in the last decade. In this review most of the currently available modeling tools are introduced and illustrated on the most challenging problems in zeolite science. Directions for future model developments will be given.
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  28. 28
    Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 47, 558– 561,  DOI: 10.1103/PhysRevB.47.558
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    28
    Ab initio molecular dynamics of liquid metals
    Kresse, G.; Hafner, J.
    Physical Review B: Condensed Matter and Materials Physics (1993), 47 (1), 558-61CODEN: PRBMDO; ISSN:0163-1829.
    The authors present ab initio quantum-mech. mol.-dynamics calcns. based on the calcn. of the electronic ground state and of the Hellmann-Feynman forces in the local-d. approxn. at each mol.-dynamics step. This is possible using conjugate-gradient techniques for energy minimization, and predicting the wave functions for new ionic positions using sub-space alignment. This approach avoids the instabilities inherent in quantum-mech. mol.-dynamics calcns. for metals based on the use of a factitious Newtonian dynamics for the electronic degrees of freedom. This method gives perfect control of the adiabaticity and allows one to perform simulations over several picoseconds.
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  29. 29
    Kresse, G.; Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal amorphous-semiconductor transition in germanium. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 49, 14251– 14269,  DOI: 10.1103/PhysRevB.49.14251
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    29
    Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium
    Kresse, G.; Hafner, J.
    Physical Review B: Condensed Matter and Materials Physics (1994), 49 (20), 14251-69CODEN: PRBMDO; ISSN:0163-1829.
    The authors present ab initio quantum-mech. mol.-dynamics simulations of the liq.-metal-amorphous-semiconductor transition in Ge. The simulations are based on (a) finite-temp. d.-functional theory of the 1-electron states, (b) exact energy minimization and hence calcn. of the exact Hellmann-Feynman forces after each mol.-dynamics step using preconditioned conjugate-gradient techniques, (c) accurate nonlocal pseudopotentials, and (d) Nose' dynamics for generating a canonical ensemble. This method gives perfect control of the adiabaticity of the electron-ion ensemble and allows the authors to perform simulations over >30 ps. The computer-generated ensemble describes the structural, dynamic, and electronic properties of liq. and amorphous Ge in very good agreement with expt.. The simulation allows the authors to study in detail the changes in the structure-property relation through the metal-semiconductor transition. The authors report a detailed anal. of the local structural properties and their changes induced by an annealing process. The geometrical, bounding, and spectral properties of defects in the disordered tetrahedral network are studied and compared with expt.
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  30. 30
    Kresse, G.; Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15– 50,  DOI: 10.1016/0927-0256(96)00008-0
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    30
    Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
    Kresse, G.; Furthmuller, J.
    Computational Materials Science (1996), 6 (1), 15-50CODEN: CMMSEM; ISSN:0927-0256. (Elsevier)
    The authors present a detailed description and comparison of algorithms for performing ab-initio quantum-mech. calcns. using pseudopotentials and a plane-wave basis set. The authors will discuss: (a) partial occupancies within the framework of the linear tetrahedron method and the finite temp. d.-functional theory, (b) iterative methods for the diagonalization of the Kohn-Sham Hamiltonian and a discussion of an efficient iterative method based on the ideas of Pulay's residual minimization, which is close to an order N2atoms scaling even for relatively large systems, (c) efficient Broyden-like and Pulay-like mixing methods for the charge d. including a new special preconditioning optimized for a plane-wave basis set, (d) conjugate gradient methods for minimizing the electronic free energy with respect to all degrees of freedom simultaneously. The authors have implemented these algorithms within a powerful package called VAMP (Vienna ab-initio mol.-dynamics package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semi-conducting surfaces, phonons in simple metals, transition metals and semiconductors) and turned out to be very reliable.
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  31. 31
    Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 11169– 11186,  DOI: 10.1103/PhysRevB.54.11169
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    31
    Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
    Kresse, G.; Furthmueller, J.
    Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
    The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
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  32. 32
    Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865– 3868,  DOI: 10.1103/PhysRevLett.77.3865
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    32
    Generalized gradient approximation made simple
    Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
    Physical Review Letters (1996), 77 (18), 3865-3868CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
    Generalized gradient approxns. (GGA's) for the exchange-correlation energy improve upon the local spin d. (LSD) description of atoms, mols., and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental consts. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential.
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  33. 33
    Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 2010, 132, 154104,  DOI: 10.1063/1.3382344
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    33
    A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
    Grimme, Stefan; Antony, Jens; Ehrlich, Stephan; Krieg, Helge
    Journal of Chemical Physics (2010), 132 (15), 154104/1-154104/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    The method of dispersion correction as an add-on to std. Kohn-Sham d. functional theory (DFT-D) has been refined regarding higher accuracy, broader range of applicability, and less empiricism. The main new ingredients are atom-pairwise specific dispersion coeffs. and cutoff radii that are both computed from first principles. The coeffs. for new eighth-order dispersion terms are computed using established recursion relations. System (geometry) dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination nos. (CN). They are used to interpolate between dispersion coeffs. of atoms in different chem. environments. The method only requires adjustment of two global parameters for each d. functional, is asymptotically exact for a gas of weakly interacting neutral atoms, and easily allows the computation of at. forces. Three-body nonadditivity terms are considered. The method has been assessed on std. benchmark sets for inter- and intramol. noncovalent interactions with a particular emphasis on a consistent description of light and heavy element systems. The mean abs. deviations for the S22 benchmark set of noncovalent interactions for 11 std. d. functionals decrease by 15%-40% compared to the previous (already accurate) DFT-D version. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C6 coeffs. also lead to a much better description of large (infinite) systems as shown for graphene sheets and the adsorption of benzene on an Ag(111) surface. For graphene it is found that the inclusion of three-body terms substantially (by about 10%) weakens the interlayer binding. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in mols. and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems. (c) 2010 American Institute of Physics.
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  34. 34
    Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775,  DOI: 10.1103/PhysRevB.59.1758
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    34
    From ultrasoft pseudopotentials to the projector augmented-wave method
    Kresse, G.; Joubert, D.
    Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
    The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
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  35. 35
    Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17953– 17979,  DOI: 10.1103/PhysRevB.50.17953
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    35
    Projector augmented-wave method
    Blochl
    Physical review. B, Condensed matter (1994), 50 (24), 17953-17979 ISSN:0163-1829.
    There is no expanded citation for this reference.
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  36. 36
    Ghysels, A.; Van Neck, D.; Waroquier, M. Cartesian formulation of the mobile block Hessian approach to vibrational analysis in partially optimized systems. J. Chem. Phys. 2007, 127, 164108,  DOI: 10.1063/1.2789429
    Google Scholar
    36
    Cartesian formulation of the mobile block Hessian approach to vibrational analysis in partially optimized systems
    Ghysels, A.; Van Neck, D.; Waroquier, M.
    Journal of Chemical Physics (2007), 127 (16), 164108/1-164108/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    Partial optimization is a useful technique to reduce the computational load in simulations of extended systems. In such nonequil. structures, the accurate calcn. of localized vibrational modes can be troublesome, since the std. normal mode anal. becomes inappropriate. In a previous paper, the mobile block Hessian (MBH) approach was presented to deal with the vibrational anal. in partially optimized systems. In the MBH model, the nonoptimized regions of the system are represented by one or several blocks, which can move as rigid bodies with respect to the atoms of the optimized region. In this way unphys. imaginary frequencies are avoided and the translational/rotational invariance of the potential energy surface is fully respected. In this paper we focus on issues concerning the practical numerical implementation of the MBH model. The MBH normal mode equations are worked out for several coordinate choices. The introduction of a consistent group-theor. notation facilitates the treatment of both the case of a single block and the case of multiple blocks. Special attention is paid to the formulation in terms of Cartesian variables, in order to provide a link with the std. output of common mol. modeling programs.
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  37. 37
    Reetz, M. T.; Meiswinkel, A.; Mehler, G.; Angermund, K.; Graf, M.; Thiel, W.; Mynott, R.; Blackmond, D. G. Why Are BINOL-Based Monophosphites Such Efficient Ligands in Rh-Catalyzed Asymmetric Olefin Hydrogenation?. J. Am. Chem. Soc. 2005, 127, 10305– 10313,  DOI: 10.1021/ja052025+
    Google Scholar
    37
    Why Are BINOL-Based Monophosphites Such Efficient Ligands in Rh-Catalyzed Asymmetric Olefin Hydrogenation?
    Reetz, Manfred T.; Meiswinkel, Andreas; Mehler, Gerlinde; Angermund, Klaus; Graf, Martin; Thiel, Walter; Mynott, Richard; Blackmond, Donna G.
    Journal of the American Chemical Society (2005), 127 (29), 10305-10313CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Whereas recent synthetic studies concerning Rh-catalyzed olefin hydrogenation based on BINOL-derived monodentate phosphites have resulted in an efficient and economically attractive preparative method, very little is known concerning the source of the unexpectedly high levels of enantioselectivity (ee often 90-99%). The present mechanistic study, which includes the NMR characterization of the precatalysts, kinetic measurements with focus on nonlinear effects, and DFT calcns., constitutes a first step in understanding this hydrogenation system. The two most important features which have emerged from these efforts are the following: (1) two monodentate P-ligands are attached to rhodium, and (2) the lock-and-key mechanism holds, in which the thermodn. of Rh/olefin complexation with formation of the major and minor diastereomeric intermediates dictates the stereochem. outcome. The major diastereomer leads to the favored enantiomeric product, which is opposite to the state of affairs in classical Rh-catalyzed olefin hydrogenation based on chiral chelating diphosphines (anti lock-and-key mechanism as proposed by Halpern).
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  38. 38
    Donoghue, P. J.; Helquist, P.; Norrby, P. O.; Wiest, O. Development of a Q2MM Force Field for the Asymmetric Rhodium Catalyzed Hydrogenation of Enamides. J. Chem. Theory Comput. 2008, 4, 1313– 1323,  DOI: 10.1021/ct800132a
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    38
    Development of a Q2MM Force Field for the Asymmetric Rhodium Catalyzed Hydrogenation of Enamides
    Donoghue, Patrick J.; Helquist, Paul; Norrby, Per-Ola; Wiest, Olaf
    Journal of Chemical Theory and Computation (2008), 4 (8), 1313-1323CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)
    The rhodium catalyzed asym. hydrogenation of enamides to generate amino acid products and derivs. is a widely used method to generate unnatural amino acids. The choice of a chiral ligand is of utmost importance in this reaction and is often based on high throughput screening or simply trial and error. A virtual screening method can greatly increase the speed of the ligand screening process by calcg. expected enantiomeric excesses from relative energies of diastereomeric transition states. Utilizing the Q2MM method, new mol. mechanics parameters are derived to model the hydride transfer transition state in the reaction. The new parameters were based off of structures calcd. at the B3LYP/LACVP** level of theory and added to the MM3* force field. The new parameters were validated against a test set of exptl. data utilizing a wide range of bis-phosphine ligands. The computational model agreed with exptl. data well overall, with an unsigned mean error of 0.6 kcal/mol against a set of 18 data points from expt. The major errors in the computational model were due either to large energetic errors at high e.e., still resulting in qual. agreement, or cases where large steric interactions prevent the reaction from proceeding as expected.
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  39. 39
    Ghysels, A.; Verstraelen, T.; Hemelsoet, K.; Waroquier, M.; Van Speybroeck, V. TAMkin: A Versatile Package for Vibrational Analysis and Chemical Kinetics. J. Chem. Inf. Model. 2010, 50, 1736– 1750,  DOI: 10.1021/ci100099g
    Google Scholar
    39
    TAMkin: A Versatile Package for Vibrational Analysis and Chemical Kinetics
    Ghysels, An; Verstraelen, Toon; Hemelsoet, Karen; Waroquier, Michel; Van Speybroeck, Veronique
    Journal of Chemical Information and Modeling (2010), 50 (9), 1736-1750CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)
    TAMkin is a program for the calcn. and anal. of normal modes, thermochem. properties and chem. reaction rates. At present, the output from the frequently applied software programs ADF, CHARMM, CPMD, CP2K, Gaussian, Q-Chem, and VASP can be analyzed. The normal-mode anal. can be performed using a broad variety of advanced models, including the std. full Hessian, the Mobile Block Hessian, the Partial Hessian Vibrational approach, the Vibrational Subsystem Anal. with or without mass matrix correction, the Elastic Network Model, and other combinations. TAMkin is readily extensible because of its modular structure. Chem. kinetics of unimol. and bimol. reactions can be analyzed in a straightforward way using conventional transition state theory, including tunneling corrections and internal rotor refinements. A sensitivity anal. can also be performed, providing important insight into the theor. error margins on the kinetic parameters. Two extensive examples demonstrate the capabilities of TAMkin: the conformational change of the biol. system adenylate kinase is studied, as well as the reaction kinetics of the addn. of ethene to the Et radical. The important feature of batch processing large amts. of data is highlighted by performing an extended level of theory study, which TAMkin can automate significantly.
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  40. 40
    Van de Vondele, J.; Krack, M.; Mohamed, F.; Parrinello, M.; Chassaing, T.; Hutter, J. QUICKSTEP: Fast and accurate density functional calculations using a mixed Gaussian and plane waves approach. Comput. Phys. Commun. 2005, 167, 103– 128,  DOI: 10.1016/j.cpc.2004.12.014
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    40
    QUICKSTEP: fast and accurate density functional calculations using a mixed Gaussian and plane waves approach
    VandeVondele, Joost; Krack, Matthias; Mohamed, Fawzi; Parrinello, Michele; Chassaing, Thomas; Hutter, Juerg
    Computer Physics Communications (2005), 167 (2), 103-128CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)
    We present the Gaussian and plane waves (GPW) method and its implementation in which is part of the freely available program package CP2K. The GPW method allows for accurate d. functional calcns. in gas and condensed phases and can be effectively used for mol. dynamics simulations. We show how derivs. of the GPW energy functional, namely ionic forces and the Kohn-Sham matrix, can be computed in a consistent way. The computational cost of computing the total energy and the Kohn-Sham matrix is scaling linearly with the system size, even for condensed phase systems of just a few tens of atoms. The efficiency of the method allows for the use of large Gaussian basis sets for systems up to 3000 atoms, and we illustrate the accuracy of the method for various basis sets in gas and condensed phases. Agreement with basis set free calcns. for single mols. and plane wave based calcns. in the condensed phase is excellent. Wave function optimization with the orbital transformation technique leads to good parallel performance, and outperforms traditional diagonalisation methods. Energy conserving Born-Oppenheimer dynamics can be performed, and a highly efficient scheme is obtained using an extrapolation of the d. matrix. We illustrate these findings with calcns. using commodity PCs as well as supercomputers.
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  41. 41
    Yang, K.; Zheng, J.; Zhao, Y.; Truhlar, D. G. Tests of the RPBE, revPBE, τ-HCTHhyb, ωB97X-D, and MOHLYP density functional approximations and 29 others against representative databases for diverse bond energies and barrier heights in catalysis. J. Chem. Phys. 2010, 132, 164117,  DOI: 10.1063/1.3382342
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    41
    Tests of the RPBE, revPBE, τ-HCTHhyb, ωB97X-D, and MOHLYP density functional approximations and 29 others against representative databases for diverse bond energies and barrier heights in catalysis
    Yang, Ke; Zheng, Jing-Jing; Zhao, Yan; Truhlar, Donald G.
    Journal of Chemical Physics (2010), 132 (16), 164117/1-164117/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    Thirty four d. functional approxns. are tested against two diverse databases, one with 18 bond energies and one with 24 barriers. These two databases are chosen to include bond energies and barrier heights which are relevant to catalysis, and in particular the bond energy database includes metal-metal bonds, metal-ligand bonds, alkyl bond dissocn. energies, and atomization energies of small main group mols. Two revised versions of the Perdew-Burke-Ernzerhof (PBE) functional, namely the RPBE and revPBE functionals, widely used for catalysis, do improve the performance of PBE against the two diverse databases, but give worse results than B3LYP (which denotes the combination of Becke's 3-parameter hybrid treatment with Lee-Yang-Parr correlation functional). Our results show that the Minnesota functionals, M05, M06, and M06-L give the best performance for the two diverse databases, which suggests that they deserve more attention for applications to catalysis. We also obtain notably good performance with the τ-HCTHhyb, ωB97X-D, and MOHLYP functional (where MOHLYP denotes the combination of the OptX exchange functional as modified by Schultz, Zhao, and Truhlar with half of the LYP correlation functional). (c) 2010 American Institute of Physics.
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  42. 42
    Goedecker, S.; Teter, M.; Hutter, J. Separable dual-space Gaussian pseudopotentials. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 1703– 1710,  DOI: 10.1103/PhysRevB.54.1703
    Google Scholar
    42
    Separable dual-space Gaussian pseudopotentials
    Goedecker, S.; Teter, M.; Hutter, J.
    Physical Review B: Condensed Matter (1996), 54 (3), 1703-1710CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
    We present pseudopotential coeffs. for the first two rows of the Periodic Table. The pseudopotential is of an analytic form that gives optimal efficiency in numerical calculations using plane waves as a basis set. At most, even coeffs. are necessary to specify its analytic form. It is separable and has optimal decay properties in both real and Fourier space. Because of this property, the application of the nonlocal part of the pseudopotential to a wave function can be done efficiently on a grid in real space. Real space integration is much faster for large systems than ordinary multiplication in Fourier space, since it shows only quadratic scaling with respect to the size of the system. We systematically verify the high accuracy of these pseudopotentials by extensive at. and mol. test calcns.
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  43. 43
    Lippert, G.; Hutter, J.; Parrinello, M. The Gaussian and augmented-plane-wave density functional method for ab initio molecular dynamics simulations. Theor. Chem. Acc. 1999, 103, 124– 140,  DOI: 10.1007/s002140050523
    Google Scholar
    43
    The Gaussian and augmented-plane-wave density functional method for ab initio molecular dynamics simulations
    Lippert, Gerald; Hutter, Jurg; Parrinello, Michele
    Theoretical Chemistry Accounts (1999), 103 (2), 124-140CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)
    A new algorithm for d.-functional-theory-based ab initio mol. dynamics simulations is presented. The Kohn-Sham orbitals are expanded in Gaussian-type functions and an APW-type approach is used to represent the electronic d. This extends previous work of ours where the d. was expanded only in plane waves. We describe the total d. in a smooth extended part which we represent in plane waves as in our previous work and parts localized close to the nuclei which are expanded in Gaussians. Using this representation of the charge we show how the localized and extended part can be treated sep., achieving a computational cost for the calcn. of the Kohn-Sham matrix that scales with the system size N as O(N log N). Furthermore, we are able to reduce drastically the size of the plane-wave basis. In addn., we introduce a multiple-cutoff method that improves considerably the performance of this approach. Finally, we demonstrate with a series of numerical examples the accuracy and efficiency of the new algorithm, both for electronic structure calcns. and for ab initio mol. dynamics simulations.
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  44. 44
    Lippert, G.; Hutter, J.; Parrinello, M. A hybrid Gaussian and plane wave density functional scheme. Mol. Phys. 1997, 92, 477– 488,  DOI: 10.1080/00268979709482119
    Google Scholar
    44
    A hybrid Gaussian and plane wave density functional scheme
    Lippert, Gerald; Hutter, Juerg; Parrinello, Michele
    Molecular Physics (1997), 92 (3), 477-487CODEN: MOPHAM; ISSN:0026-8976. (Taylor & Francis)
    A d.-functional theory-based algorithm for periodic and nonperiodic ab initio calcns. is presented. This scheme uses pseudopotentials in order to integrate out the core electrons from the problem. The valence pseudo wave functions are expanded in Gaussian-type orbitals and the d. is represented in a plane wave auxiliary basis. The Gaussian basis functions make it possible to use the efficient anal. integration schemes and screening algorithms of quantum chem. Novel recursion relations are developed for the calcn. of the matrix elements of the d.-dependent Kohn-Sham self-consistent potential. At the same time the use of a plane wave basis for the electron d. permits efficient calcn. of the Hartree energy using fast Fourier transforms, thus circumventing one of the major bottlenecks of std. Gaussian based calcns. Furthermore, this algorithm avoids the fitting procedures that go along with intermediate basis sets for the charge d. The performance and accuracy of this new scheme are discussed and selected examples are given.
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  45. 45
    Nosé, S. A molecular dynamics method for simulations in the canonical ensemble. Mol. Phys. 1984, 52, 255– 268,  DOI: 10.1080/00268978400101201
    Google Scholar
    45
    A molecular dynamics method for simulations in the canonical ensemble
    Nose, Shuichi
    Molecular Physics (1984), 52 (2), 255-68CODEN: MOPHAM; ISSN:0026-8976.
    A mol. dynamics simulation method is proposed which can generate configurations belonging to the canonical (T, V, N) ensemble or the const. temp. const. pressure (T, P, N) ensemble. The phys. system of interest consists of N particles (f degrees of freedom), to which an external, macroscopic variable and its conjugate momentum are added. This device allows the total energy of the phys. system to fluctuate. The equil. distribution of the energy coincides with the canonical distribution both in momentum and in coordinate space. The method is tested for an at. fluid (Ar) and works well.
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  46. 46
    Martyna, G. J.; Klein, M. L.; Tuckerman, M. Nosé-Hoover chains: The canonical ensemble via continuous dynamics. J. Chem. Phys. 1992, 97, 2635– 2643,  DOI: 10.1063/1.463940
    Google Scholar
    There is no corresponding record for this reference.
  47. 47
    Martyna, G. J.; Tobias, D. J.; Klein, M. L. Constant pressure molecular dynamics algorithms. J. Chem. Phys. 1994, 101, 4177– 4189,  DOI: 10.1063/1.467468
    Google Scholar
    47
    Constant pressure molecular dynamics algorithms
    Martyna, Glenn J.; Tobias, Douglas J.; Klein, Michael L.
    Journal of Chemical Physics (1994), 101 (5), 4177-89CODEN: JCPSA6; ISSN:0021-9606.
    Modularly invariant equations of motion are derived that generate the isothermal-isobaric ensemble as their phase space avs. Isotropic vol. fluctuations and fully flexible simulation cells as well as a hybrid scheme that naturally combines the two motions are considered. The resulting methods are tested on two problems, a particle in a one-dimensional periodic potential and a spherical model of C60 in the solid/fluid phase.
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  48. 48
    Tribello, G. A.; Bonomi, M.; Branduardi, D.; Camilloni, C.; Bussi, G. PLUMED 2: New feathers for an old bird. Comput. Phys. Commun. 2014, 185, 604– 613,  DOI: 10.1016/j.cpc.2013.09.018
    Google Scholar
    48
    PLUMED 2: New feathers for an old bird
    Tribello, Gareth A.; Bonomi, Massimiliano; Branduardi, Davide; Camilloni, Carlo; Bussi, Giovanni
    Computer Physics Communications (2014), 185 (2), 604-613CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)
    Enhancing sampling and analyzing simulations are central issues in mol. simulation. Recently, we introduced PLUMED, an open-source plug-in that provides some of the most popular mol. dynamics (MD) codes with implementations of a variety of different enhanced sampling algorithms and collective variables (CVs). The rapid changes in this field, in particular new directions in enhanced sampling and dimensionality redn. together with new hardware, require a code that is more flexible and more efficient. We therefore present PLUMED 2 here-a complete rewrite of the code in an object-oriented programming language (C++). This new version introduces greater flexibility and greater modularity, which both extends its core capabilities and makes it far easier to add new methods and CVs. It also has a simpler interface with the MD engines and provides a single software library contg. both tools and core facilities. Ultimately, the new code better serves the ever-growing community of users and contributors in coping with the new challenges arising in the field.
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  49. 49
    Cnudde, P.; De Wispelaere, K.; Vanduyfhuys, L.; Demuynck, R.; Waroquier, M.; Van Speybroeck, V.; Van der Mynsbrugge, J. How Chain Length and Branching Influence the Alkene Cracking Reactivity on H-ZSM-5. ACS Catal. 2018, 8, 9579– 9595,  DOI: 10.1021/acscatal.8b01779
    Google Scholar
    49
    How Chain Length and Branching Influence the Alkene Cracking Reactivity on H-ZSM-5
    Cnudde, Pieter; De Wispelaere, Kristof; Vanduyfhuys, Louis; Demuynck, Ruben; Van der Mynsbrugge, Jeroen; Waroquier, Michel; Van Speybroeck, Veronique
    ACS Catalysis (2018), 8 (10), 9579-9595CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    Catalytic alkene cracking on H-ZSM-5 involves a complex reaction network with many possible reaction routes and often elusive intermediates. Herein, advanced mol. dynamics simulations at 773 K, a typical cracking temp., are performed to clarify the nature of the intermediates and to elucidate dominant cracking pathways at operating conditions. A series of C4-C8 alkene intermediates are investigated to evaluate the influence of chain length and degree of branching on their stability. Our simulations reveal that linear, secondary carbenium ions are relatively unstable, although their lifetime increases with carbon no. Tertiary carbenium ions, on the other hand, are shown to be very stable, irresp. of the chain length. Highly branched carbenium ions, though, tend to rapidly rearrange into more stable cationic species, either via cracking or isomerization reactions. Dominant cracking pathways were detd. by combining these insights on carbenium ion stability with intrinsic free energy barriers for various octene β-scission reactions, detd. via umbrella sampling simulations at operating temp. (773 K). Cracking modes A (3° → 3°) and B2 (3° → 2°) are expected to be dominant at operating conditions, whereas modes B1 (2° → 3°), C (2° → 2°), D2 (2° → 1°), and E2 (3° → 1°) are expected to be less important. All β-scission modes in which a transition state with primary carbocation character is involved have high intrinsic free energy barriers. Reactions starting from secondary carbenium ions will contribute less as these intermediates are short living at the high cracking temp. Our results show the importance of simulations at operating conditions to properly evaluate the carbenium ion stability for β-scission reactions and to assess the mobility of all species in the pores of the zeolite.
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  50. 50
    Kästner, J. Umbrella sampling. WIREs Comput. Mol. Sci. 2011, 1, 932– 942,  DOI: 10.1002/wcms.66
    Google Scholar
    There is no corresponding record for this reference.
  51. 51
    Kumar, S.; Rosenberg, J. M.; Bouzida, D.; Swendsen, R. H.; Kollman, P. A. The weighted histogram analysis method for free-energy calculations on biomolecules. I. The method. J. Comput. Chem. 1992, 13, 1011– 1021,  DOI: 10.1002/jcc.540130812
    Google Scholar
    51
    The weighted histogram analysis method for free-energy calculations on biomolecules. I. The method
    Kumar, Shankar; Bouzida, Djamal; Swendsen, Robert H.; Kollman, Peter A.; Rosenberg, John M.
    Journal of Computational Chemistry (1992), 13 (8), 1011-21CODEN: JCCHDD; ISSN:0192-8651.
    The Weighted Histogram Anal. Method (WHAM), an extension of Ferrenberg and Swendsen's Multiple Histogram Technique, has been applied for the first time on complex biomol. Hamiltonians. The method is presented here as an extension of the Umbrella Sampling method for free-energy and Potential of Mean Force calcns. This algorithm possesses the following advantages over methods that are currently employed: (1) it provides a built-in est. of sampling errors thereby yielding objective ests. of the optimal location and length of addnl. simulations needed to achieve a desired level of precision; (2) it yields the "best" value of free energies by taking into account all the simulations so as to minimize the statistical errors; (3) in addn. to optimizing the links between simulations, it also allows multiple overlaps of probability distributions for obtaining better ests. of the free-energy differences. By recasting the Ferrenberg-Swendsen Multiple Histogram equations in a form suitable for mol. mechanics type Hamiltonians, we have demonstrated the feasibility and robustness of this method by applying it to a test problem of the generation of the Potential of Mean Force profile of the pseudorotation phase angle of the sugar ring in deoxyadenosine.
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  52. 52
    Souaille, M.; Roux, B. Extension to the weighted histogram analysis method: combining umbrella sampling with free energy calculations. Comput. Phys. Commun. 2001, 135, 40– 57,  DOI: 10.1016/S0010-4655(00)00215-0
    Google Scholar
    52
    Extension to the weighted histogram analysis method: combining umbrella sampling with free energy calculations
    Souaille, M.; Roux, B.
    Computer Physics Communications (2001), 135 (1), 40-57CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier Science B.V.)
    The Weighted Histogram Anal. Method (WHAM) of Kumar et al. (J. Comput. Chem. 13 (1992) 1011), is used to combine free energy perturbations with umbrella sampling calcns. The formulation is general and allows optimal calcn. of the free energies from a set of mol. dynamics simulations generated in the presence of arbitrary biasing umbrella sampling window potentials. The method yields the free energy assocd. with a given simulation as well as the probability distribution of the mol. system configurations by extg. the information contained in all the biased simulations (the windows) in an optimal way. The method presents some advantages compared to the std. free energy perturbation (FEP) and thermodn. integration (TI) methods, because the window potential can be used for restricting the conformational space to specific regions during free energy calcns.
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  53. 53
    Cheng, K.; Zhou, W.; Kang, J.; He, S.; Shi, S.; Zhang, Q.; Pan, Y.; Wen, W.; Wang, Y. Bifunctional Catalysts for One-Step Conversion of Syngas into Aromatics with Excellent Selectivity and Stability. Chem. 2017, 3, 334– 347,  DOI: 10.1016/j.chempr.2017.05.007
    Google Scholar
    53
    Bifunctional Catalysts for One-Step Conversion of Syngas into Aromatics with Excellent Selectivity and Stability
    Cheng, Kang; Zhou, Wei; Kang, Jincan; He, Shun; Shi, Shulin; Zhang, Qinghong; Pan, Yang; Wen, Wu; Wang, Ye
    Chem (2017), 3 (2), 334-347CODEN: CHEMVE; ISSN:2451-9294. (Cell Press)
    Syngas (CO/H2) is a key platform for chem. utilization of non-petroleum carbon resources. Among syngas transformation routes, the direct synthesis of aroms., which are among the most important bulk chems., is less successful because of the limited selectivity and poor catalyst stability. We report a successful design of bifunctional catalysts composed of Zn-doped ZrO2 nanoparticles dispersed on zeolite H-ZSM-5 for one-step conversion of syngas to aroms. with high selectivity and stability. Aroms. with 80% selectivity at CO conversion of 20% were achieved, and there was no catalyst deactivation in 1,000 h. Methanol and di-Me ether were formed as major intermediates on Zn-doped ZrO2, which were subsequently converted into aroms. on H-ZSM-5 via olefins. We discovered a self-promotion mechanism of CO in the selective formation of aroms. As well as being a reactant, CO facilitates the removal of hydrogen species formed on H-ZSM-5 in the dehydrogenative aromatization of olefins.
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  54. 54
    Guisnet, M.; Gnep, N. S.; Alario, F. Aromatization of short chain alkanes on zeolite catalysts. Appl. Catal., A 1992, 89, 1– 30,  DOI: 10.1016/0926-860X(92)80075-N
    Google Scholar
    54
    Aromatization of short chain alkanes on zeolite catalysts
    Guisnet, M.; Gnep, N. S.; Alario, F.
    Applied Catalysis, A: General (1992), 89 (1), 1-30CODEN: ACAGE4; ISSN:0926-860X.
    A review with 95 refs. covering principally GaHZSM 5 and Ga-substituted MFI-type zeolite catalysts.
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  55. 55
    Dutta Chowdhury, A.; Paioni, A. L.; Houben, K.; Whiting, G. T.; Baldus, M.; Weckhuysen, B. M. Bridging the Gap between the Direct and Hydrocarbon Pool Mechanisms of the Methanol-to-Hydrocarbon Process. Angew. Chem., Int. Ed. 2018, 57, 8095– 8099,  DOI: 10.1002/anie.201803279
    Google Scholar
    There is no corresponding record for this reference.
  56. 56
    Yarulina, I.; Dutta Chowdhury, A.; Meirer, F.; Weckhuysen, B. M.; Gascon, J. Recent Trends and Fundamental Insights in the Methanol-to-Olefins Process. Nat. Catal. 2018, 1, 398– 411,  DOI: 10.1038/s41929-018-0078-5
    Google Scholar
    56
    Recent trends and fundamental insights in the methanol-to-hydrocarbons process
    Yarulina, Irina; Chowdhury, Abhishek Dutta; Meirer, Florian; Weckhuysen, Bert M.; Gascon, Jorge
    Nature Catalysis (2018), 1 (6), 398-411CODEN: NCAACP; ISSN:2520-1158. (Nature Research)
    The prodn. of high-demand chem. commodities such as ethylene and propylene (methanol-to-olefins), hydrocarbons (methanol-to-hydrocarbons), gasoline (methanol-to-gasoline) and aroms. (methanol-to-aroms.) from methanol-obtainable from alternative feedstocks, such as carbon dioxide, biomass, waste or natural gas through the intermediate formation of synthesis gas-has been central to research in both academia and industry. Although discovered in the late 1970s, this catalytic technol. has only been industrially implemented over the past decade, with a no. of large com. plants already operating in Asia. However, as is the case for other technologies, industrial maturity is not synonymous with full understanding. For this reason, research is still intense and a no. of important discoveries have been reported over the last few years. In this review, we summarize the most recent advances in mechanistic understanding-including direct C-C bond formation during the induction period and the promotional effect of zeolite topol. and acidity on the alkene cycle-and correlate these insights to practical aspects in terms of catalyst design and engineering.
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  57. 57
    Dutta Chowdhury, A.; Houben, K.; Whiting, G. T.; Mokhtar, M.; Asiri, A. M.; Al-Thabaiti, S. A.; Baldus, M.; Weckhuysen, B. M.; Basahel, S. N. Initial carbon-carbon bond formation during the early stages of the methanol-to-olefin process proven by zeolite-trapped acetate and methyl acetate. Angew. Chem., Int. Ed. 2016, 55, 15840– 15845,  DOI: 10.1002/anie.201608643
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    There is no corresponding record for this reference.
  58. 58
    Ristanović, Z.; Dutta Chowdhury, A.; Brogaard, R. Y.; Houben, K.; Baldus, M.; Hofkens, J.; Roeffaers, M. B. J.; Weckhuysen, B. M. Reversible and Site-Dependent Proton-Transfer in Zeolites Uncovered at the Single-Molecule Level. J. Am. Chem. Soc. 2018, 140, 14195– 14205,  DOI: 10.1021/jacs.8b08041
    Google Scholar
    58
    Reversible and Site-Dependent Proton-Transfer in Zeolites Uncovered at the Single-Molecule Level
    Ristanovic, Zoran; Chowdhury, Abhishek Dutta; Brogaard, Rasmus Y.; Houben, Klaartje; Baldus, Marc; Hofkens, Johan; Roeffaers, Maarten B. J.; Weckhuysen, Bert M.
    Journal of the American Chemical Society (2018), 140 (43), 14195-14205CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Zeolite activity and selectivity is often detd. by the underlying proton and hydrogen-transfer reaction pathways. For the first time, we use single-mol. fluorescence microscopy to directly follow the real-time behavior of individual styrene-derived carbocationic species formed within zeolite ZSM-5. We find that intermittent fluorescence and remarkable photostability of carbocationic intermediates strongly depend on the local chem. environment imposed by zeolite framework and guest solvent mols. The carbocationic stability can be addnl. altered by changing para-substituent on the styrene moiety, as suggested by DFT calcns. Thermodynamically unstable carbocations are more likely to switch between fluorescent (carbocationic) and dark (neutral) states. However, the rate consts. of this reversible change can significantly differ among individual carbocations, depending on their exact location in the zeolite framework. The lifetimes of fluorescent states and reversibility of the process can be addnl. altered by changing the interaction between dimeric carbocations and solvated Bronsted acid sites in the MFI framework. Advanced multidimensional magic angle spinning solid-state NMR spectroscopy has been employed for the accurate structural elucidation of the reaction products during the zeolite-catalyzed dimerization of styrene in order to corroborate the single-mol. fluorescence microscopy data. This complementary approach of single-mol. fluorescence microscopy, NMR, and DFT collectively indicates that the relative stability of the carbocationic and the neutral states largely depends on the substituent and the local position of the Bronsted acid site within the zeolite framework. As a consequence, new insights into the host-guest chem. between the zeolite and aroms., in terms of their surface mobility and reactivity, have been obtained.
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  59. 59
    Persson, I. Hydrated metal ions in aqueous solution: How regular are their structures?. Pure Appl. Chem. 2010, 82, 1901– 1917,  DOI: 10.1351/PAC-CON-09-10-22
    Google Scholar
    59
    Hydrated metal ions in aqueous solution: how regular are their structures?
    Persson, Ingmar
    Pure and Applied Chemistry (2010), 82 (10), 1901-1917CODEN: PACHAS; ISSN:0033-4545. (International Union of Pure and Applied Chemistry)
    A review. The hydration reaction is defined as the transfer of an ion or neutral chem. species from the gaseous phase into water, Mn+(g) → Mn+(aq). In this process, water mols. bind to metal ions through ion-dipole bonds of mainly electrostatic character. The hydration reaction is always strongly exothermic with increasing heat of hydration with increasing charge d. of the ion. The structures of the hydrated metal ions in aq. soln. display a variety of configurations depending on the size and electronic properties of the metal ion. The basic configurations of hydrated metal ions in aq. soln. are tetrahedral, octahedral, square antiprismatic, and tricapped trigonal prismatic. This paper gives an overview of the structures of hydrated metal ions in aq. soln. with special emphasis on those with a non-regular coordination figure. Metal ions without d-electrons in the valance shell form regular aqua complexes with a coordination figure, allowing a max. no. of water mols. to be clustered around the metal ion. This no. is dependent on the ratio of the metal ion radius to the at. radius of oxygen in a coordinated water mol. (1.34 Å). The lighter lanthanoid(III) ions have a regular tricapped trigonal prismatic configuration with the M-O distance to the capping water mols. somewhat longer than to the prismatic ones. However, with increasing at. no. of the lanthanoid(III) ions, an increasing distortion of the capping water mols. is obsd., resulting in a partial loss of water mols. in the capping positions for the heaviest lanthanoids. Metal ions with d4 and d9 valance shell electron configuration, as chromium(II) and copper(II), resp., have Jahn-Teller distorted aqua complexes. Metal ions with low charge and ability to form strong covalent bonds, as silver(I), mercury(II), palladium(II), and platinum(II), often display distorted coordination figures due to the second-order Jahn-Teller effect. Metal ions with d10s2 valence shell electron configuration may have a stereochem. active lone electron pair (hemi-directed complexes) or an inactive one (holo-directed). The hydrated tin(II), lead(II), and thallium(I) ions are hemi-directed in aq. soln., while the hydrated bismuth(III) ion is holo-directed. The structures of the hydrated cationic oxo-metal ions are reported as well.
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  60. 60
    Weitkamp, J. Catalytic Hydrocracking-Mechanisms and Versatility of the Process. ChemCatChem 2012, 4, 292– 306,  DOI: 10.1002/cctc.201100315
    Google Scholar
    60
    Catalytic Hydrocracking-Mechanisms and Versatility of the Process
    Weitkamp, Jens
    ChemCatChem (2012), 4 (3), 292-306CODEN: CHEMK3; ISSN:1867-3880. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Hydrocracking of satd. hydrocarbons can proceed by four distinctly different mechanisms. On bifunctional catalysts comprising hydrogenation/dehydrogenation and Broensted acid sites alkenes and carbocations occur as intermediates. The current mechanistic views of bifunctional hydrocracking of long-chain n-alkanes are discussed in detail with emphasis on the now widely accepted concept of ideal hydrocracking. Other mechanisms are hydrogenolysis and Haag-Dessau hydrocracking which proceed, resp., on monofunctional metallic and acidic catalysts. Even without a catalyst, thermal hydrocracking occurs in chain reactions via radicals. The chem. of hydrocracking naphthenes on bifunctional catalysts resembles that of alkanes. A peculiarity, however, is the pronounced reluctance of cyclic carbenium ions to undergo endocyclic β-scissions. The effect manifests itself in the so-called paring reaction, which, in turn, forms the basis for measuring the Spaciousness Index for characterizing the effective pore width of zeolitic catalysts. Hydrocracking on bifunctional catalysts is among the very important processes in modern petroleum refining. It is primarily used for converting heavy oils into diesel and jet fuel. Besides, hydrocracking is appreciated for its pronounced versatility: numerous process variants exist which help to meet specific requirements in refineries or petrochem. plants. Two recent developments are briefly discussed in this review, viz. the conversion of surplus aroms., e.g., in pyrolysis gasoline, into a synthetic feedstock for steam crackers, and quality enhancement of diesel fuel by selective ring opening of polynuclear aroms.
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  61. 61
    Kissin, Y. V. Chemical Mechanisms of Catalytic Cracking Over Solid Acidic Catalysts: Alkanes and Alkenes. Catal. Rev.: Sci. Eng. 2001, 43, 85– 146,  DOI: 10.1081/CR-100104387
    Google Scholar
    61
    Chemical mechanisms of catalytic cracking over solid acidic catalysts: alkanes and alkenes
    Kissin, Yury V.
    Catalysis Reviews - Science and Engineering (2001), 43 (1 & 2), 85-146CODEN: CRSEC9; ISSN:0161-4940. (Marcel Dekker, Inc.)
    A review with 186 refs. on the mechanisms of catalytic cracking of alkenes and alkanes over solid acidic catalysts.
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  62. 62
    Martínez-Espín, J. S.; De Wispelaere, K.; Janssens, T. V. W.; Svelle, S.; Lillerud, K. P.; Beato, P.; Van Speybroeck, V.; Olsbye, U. Hydrogen Transfer versus Methylation: On the Genesis of Aromatics Formation in the Methanol-To-Hydrocarbons Reaction over H-ZSM-5. ACS Catal. 2017, 7, 5773– 5780,  DOI: 10.1021/acscatal.7b01643
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    62
    Hydrogen Transfer versus Methylation: On the Genesis of Aromatics Formation in the Methanol-To-Hydrocarbons Reaction over H-ZSM-5
    Martinez-Espin, Juan S.; De Wispelaere, Kristof; Janssens, Ton V. W.; Svelle, Stian; Lillerud, Karl Petter; Beato, Pablo; Van Speybroeck, Veronique; Olsbye, Unni
    ACS Catalysis (2017), 7 (9), 5773-5780CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    The catalytic conversion of methanol (MeOH) and di-Me ether (DME) into fuels and chems. over zeolites (MTH process) is industrially emerging as an alternative route to conventional oil-derived processes. After 40 years of research, a detailed mechanistic understanding of the intricate reaction network is still not fully accomplished. The overall reaction is described as two competitive catalytic cycles, dominated by alkenes and arenes, which are methylated and cracked or dealkylated to form effluent products. Herein, we present the reaction of isobutene with methanol and DME as an efficient tool for measuring the relative formation rates of alkenes and arenes, and we provide detailed mechanistic insight into the hydrogen-transfer reaction. We provide exptl. and theor. evidence that manifest a strong competition of methylation and hydrogen transfer of isobutene by methanol, while methylation is substantially favored by DME. Expts. performed at higher conversion facilitate projection of the results to the product distribution obtained when using MeOH or DME as feedstock during the MTH reaction.
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  63. 63
    Buchanan, J. S.; Santiesteban, J. G.; Haag, W. O. Mechanistic Considerations in Acid-Catalyzed Cracking of Olefins. J. Catal. 1996, 158, 279– 287,  DOI: 10.1006/jcat.1996.0027
    Google Scholar
    63
    Mechanistic considerations in acid-catalyzed cracking of olefins
    Buchanan, J. S.; Santiesteban, J. G.; Haag, W. O.
    Journal of Catalysis (1996), 158 (1), 279-87CODEN: JCTLA5; ISSN:0021-9517. (Academic)
    The relative rates of cracking and resultant products distributions for cracking C5-C8 olefins over ZSM-5 at 510°C were quantified and rationalized in terms of carbenium ion mechanisms. Conditions were chosen to minimize bimol. reactions. Cracking rates increase more dramatically with carbon no. for olefins than for monomol. cracking of paraffins, as more energetically favorable modes become available for β-scission, as classified by the types of carbenium ions involved. For hexene and heptene feeds, the most-favorable β-scission mode available (C-type, involving just secondary carbenium ions, for hexene feed; B-type, involving secondary plus tertiary carbenium ions for heptene) accounted for 70-80% of the cracking. Product distribution was independent of which hexene or heptene isomer was fed, since double-bond and skeletal isomerization precedes significant cracking. For 1-octene feed, however, the olefin was nearly all cracked via secondary-tertiary and tertiary-secondary β-scission (after isomerizing to a dimethylhexene) before it isomerized further to the 2,4,4-trimethylpentene isomer, which would be required to undergo the most energetically favored (tertiary-tertiary) form of cracking. A semiquant. prediction of rates and product distribution for 1-octene cracking could be made, using rates for the various types of β-scission calcd. from results with C6-C7 feeds.
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  64. 64
    Van Speybroeck, V.; De Wispelaere, K.; Van der Mynsbrugge, J.; Vandichel, M.; Hemelsoet, K.; Waroquier, M. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev. 2014, 43, 7326– 7357,  DOI: 10.1039/C4CS00146J
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    64
    First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study
    Van Speybroeck, Veronique; De Wispelaere, Kristof; Van der Mynsbrugge, Jeroen; Vandichel, Matthias; Hemelsoet, Karen; Waroquier, Michel
    Chemical Society Reviews (2014), 43 (21), 7326-7357CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    To optimally design next generation catalysts a thorough understanding of the chem. phenomena at the mol. scale is a prerequisite. Apart from qual. knowledge on the reaction mechanism, it is also essential to be able to predict accurate rate consts. Mol. modeling has become a ubiquitous tool within the field of heterogeneous catalysis. Herein, we review current computational procedures to det. chem. kinetics from first principles, thus by using no exptl. input and by modeling the catalyst and reacting species at the mol. level. Therefore, we use the methanol-to-olefin (MTO) process as a case study to illustrate the various theor. concepts. This process is a showcase example where rational design of the catalyst was for a long time performed on the basis of trial and error, due to insufficient knowledge of the mechanism. For theoreticians the MTO process is particularly challenging as the catalyst has an inherent supramol. nature, for which not only the Bronsted acidic site is important but also org. species, trapped in the zeolite pores, must be essentially present during active catalyst operation. All these aspects give rise to specific challenges for theor. modeling. It is shown that present computational techniques have matured to a level where accurate enthalpy barriers and rate consts. can be predicted for reactions occurring at a single active site. The comparison with exptl. data such as apparent kinetic data for well-defined elementary reactions has become feasible as current computational techniques also allow predicting adsorption enthalpies with reasonable accuracy. Real catalysts are truly heterogeneous in a space- and time-like manner. Future theory developments should focus on extending our view towards phenomena occurring at longer length and time scales and integrating information from various scales towards a unified understanding of the catalyst. Within this respect mol. dynamics methods complemented with addnl. techniques to simulate rare events are now gradually making their entrance within zeolite catalysis. Recent applications have already given a flavor of the benefit of such techniques to simulate chem. reactions in complex mol. environments.
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  65. 65
    Haag, W. O.; Lago, R. M.; Rodewald, P. G. Aromatics, light olefins and gasoline from methanol: Mechanistic pathways with ZSM-5 zeolite catalyst. J. Mol. Catal. 1982, 17, 161– 169,  DOI: 10.1016/0304-5102(82)85027-X
    Google Scholar
    65
    Aromatics, light olefins and gasoline from methanol: mechanistic pathways with ZSM-5 zeolite catalyst
    Haag, W. O.; Lago, R. M.; Rodewald, P. G.
    Journal of Molecular Catalysis (1982), 17 (2-3), 161-9CODEN: JMCADS; ISSN:0304-5102.
    The conversion of MeOH [67-56-1] to hydrocarbons with zeolite ZSM-5 as catalyst provides a novel route to gasoline as well as to olefins and aroms. as chem. raw materials. The reaction is acid-catalyzed and involves alkylation of olefins and aroms. as major MeOH conversion steps, accompanied by olefin isomerization, polymn./cracking, cyclization and aromatization via H transfer. Shape-selective control of the aroms. produced results from the use of the medium pore size zeolite ZSM-5. The true kinetic paths are often disguised by diffusion/desorption effects. C2H4 is most likely the first olefinic hydrocarbon formed.
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  66. 66
    Abbot, J.; Corma, A.; Wojciechowski, B. W. The catalytic isomerization of 1-hexene on H-ZSM-5 zeolite: The effects of a shape-selective catalyst. J. Catal. 1985, 92, 398– 408,  DOI: 10.1016/0021-9517(85)90273-8
    Google Scholar
    66
    The catalytic isomerization of 1-hexene on H-ZSM-5 zeolite: the effects of a shape-selective catalyst
    Abbot, J.; Corma, A.; Wojciechowski, B. W.
    Journal of Catalysis (1985), 92 (2), 398-408CODEN: JCTLA5; ISSN:0021-9517.
    The isomerization of 1-hexene on 60/80-mesh ZSM-5 zeolite was studied at 200-280°, and the results were compared with those previously obtained for HY at 200°. The obsd. products were formed through a variety of processes including double bond shift, cis-trans isomerization, skeletal rearrangement, cracking, hydrogen transfer, polymn., and coke formation. By applying the time-on-stream theory, the products were classified as primary, secondary, or both according to their optimum performance envelope curves on product selectivity plots. At all levels of conversion, cis- and trans-2-hexene were the principal products. The ratio of the initial selectivities of cis- to trans-2-hexene at 200° was 0.54, significantly closer to the equil. value than previously found for HY zeolite. A possible explanation is given, relating to the difference in pore structure of these zeolites. The ratio of the initial rate of deprotonation to that of hydrogen shift in the hexyl carbenium ion was found to decrease with temp. At 200° this ratio was greater that that obsd. on HY. Skeletal rearrangement, polymn., cracking, and hydrogen transfer reactions all increase with temp. At 200° the total contribution from these processes accounts for significantly less product than on HY. All products of skeletal rearrangement were obsd. to be secondary. The formation of 2,3-dimethyl-1-butene appears to be restricted on ZSM-5 due to the size of this mol. Skeletal rearrangement of 1-hexene gives cis-3-methyl-2-pentene and trans-3-methyl-2-pentene as secondary products. These isomers are also formed as initial products by double bond shift of the principal impurity present in the feed, 2-ethyl-1-butene. Coke formation decreases with increasing temp. The compn. of the coke indicated that it initially consists mainly of adsorbed olefins. No arom. products could be detected and polymn. appeared to be restricted to the formation of dimers. The small amt. of paraffinic products found, and the lack of cyclization and dehydrogenation to arom. structures appear to be related to the pore size of ZSM-5.
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  67. 67
    Abbot, J.; Wojciechowski, B. W. Catalytic cracking and skeletal isomerization of n-Hexene on ZSM-5 Zeolite. Can. J. Chem. Eng. 1985, 63, 451– 461,  DOI: 10.1002/cjce.5450630314
    Google Scholar
    67
    Catalytic cracking and skeletal isomerization of n-hexene on ZSM-5 zeolite
    Abbot, J.; Wojciechowski, B. W.
    Canadian Journal of Chemical Engineering (1985), 63 (3), 451-61CODEN: CJCEA7; ISSN:0008-4034.
    With respect to coke formation in petroleum cracking and MeOH conversion to gasoline, the catalytic cracking and skeletal isomerization of hexene [25264-93-1] on ZSM-5 zeolite were studied at 350-405°. By applying the time-on-stream theory, the products of the reaction were identified as primary, secondary, or both according to their optimum performance envelope (OPE) curves on product selectivity plots. The products of cracking were almost exclusively monoolefins, of which the C3-5 olefins were stable primary or primary plus secondary products. No CH4 was found; only traces of C2 products (as C2H4) were obsd. The obsd. product distributions can be explained by a dimerization-cracking mechanism with no product species having more than twelve carbon atoms. The probability of a fragment undergoing further cracking before desorption increased with temp. and the obsd. initial selectivities must be cor. to account for this process. Methylpentene (I) [37275-41-5], formed as an unstable primary product, was the main isomer produced by skeletal rearrangement; those isomers of I derived from more stable carbenium ions predominated.
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  68. 68
    Kissin, Y. V. Chemical Mechanism of Hydrocarbon Cracking over Solid Acidic Catalysts. J. Catal. 1996, 163, 50– 62,  DOI: 10.1006/jcat.1996.0304
    Google Scholar
    68
    Chemical mechanism of hydrocarbon cracking over solid acidic catalysts
    Kissin, Yury V.
    Journal of Catalysis (1996), 163 (1), 50-62CODEN: JCTLA5; ISSN:0021-9517. (Academic)
    The article analyzes cracking reactions of isoalkanes and isoolefins over zeolite-based catalysts and discuss formation mechanisms of light reaction products under very mild conditions at 150-250°C. Cracking patterns of 28 methyl- and ethyl-branched isoalkanes show that the compns. of light products can be described by an empirical rule: (1) the reaction site is formed at the tertiary carbon atom in an isoalkane mol., (2) the predominant fission reaction involves the weakest C-C bond in the α-position to the reaction site, (3) the primary fission products are olefins. None of the cracking mechanisms described in the literature and involving reactions of carbenium and carbonium ions can adequately predict the obsd. product structures. A new cracking mechanism of isoalkanes which includes reactions between isoalkanes and Bronsted centers on the catalyst surface with the formation of transient hydrosiloxonium ions>Si-O+ (H)-C< is proposed. The ions undergo the scission of the C-C bond in their alkyl groups in the β-position to O+ with the formation of olefin mols. (which rapidly isomerize) and smaller hydrosiloxonium ions. Comparison of cracked products from olefins and alkanes with the same skeletons and the same expected carbocations shows that the resp. products are drastically different when they are formed under very mild conditions, i.e., that the cracking mechanisms of olefins and alkanes are also different. Studies of olefins with low oligomerization abilities (to prevent scrambling of the product structures) show that the olefin cracking can indeed be explained by fragmentation of carbenium ions via the β-C bond scission mechanism.
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  69. 69
    Cnudde, P.; De Wispelaere, K.; Van der Mynsbrugge, J.; Waroquier, M.; Van Speybroeck, V. Effect of temperature and branching on the nature and stability of alkene cracking intermediates in H-ZSM-5. J. Catal. 2017, 345, 53– 69,  DOI: 10.1016/j.jcat.2016.11.010
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    69
    Effect of temperature and branching on the nature and stability of alkene cracking intermediates in H-ZSM-5
    Cnudde, P.; De Wispelaere, K.; Van der Mynsbrugge, J.; Waroquier, M.; Van Speybroeck, V.
    Journal of Catalysis (2017), 345 (), 53-69CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    Catalytic cracking of alkenes takes place at elevated temps. in the order of 773-833 K. In this work, the nature of the reactive intermediates at typical reaction conditions is studied in H-ZSM-5 using a complementary set of modeling tools. Ab initio static and mol. dynamics simulations are performed on different C4-C5 alkene cracking intermediates to identify the reactive species in terms of temp. At 323 K, the prevalent intermediates are linear alkoxides, alkene π-complexes and tertiary carbenium ions. At a typical cracking temp. of 773 K, however, both secondary and tertiary alkoxides are unlikely to exist in the zeolite channels. Instead, more stable carbenium ion intermediates are found. Branched tertiary carbenium ions are very stable, while linear carbenium ions are predicted to be metastable at high temp. Our findings confirm that carbenium ions, rather than alkoxides, are reactive intermediates in catalytic alkene cracking at 773 K.
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  70. 70
    Hajek, J.; Van der Mynsbrugge, J.; De wispelaere, K.; Cnudde, P.; Vanduyfhuys, L.; Waroquier, M.; Van Speybroeck, V. On the stability and nature of adsorbed pentene in Brønsted acid zeolite H-ZSM-5 at 323 K. J. Catal. 2016, 340, 227– 235,  DOI: 10.1016/j.jcat.2016.05.018
    Google Scholar
    70
    On the stability and nature of adsorbed pentene in Bronsted acid zeolite H-ZSM-5 at 323 K
    Hajek, J.; Van der Mynsbrugge, J.; De Wispelaere, K.; Cnudde, P.; Vanduyfhuys, L.; Waroquier, M.; Van Speybroeck, V.
    Journal of Catalysis (2016), 340 (), 227-235CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    Adsorption of linear pentenes in H-ZSM-5 at 323 K is investigated using contemporary static and mol. dynamics methods. A physisorbed complex corresponding to free pentene, a π-complex and a chemisorbed species may occur. The chemisorbed species can be either a covalently bonded alkoxide or an ion pair, the so-called carbenium ion. Without finite temp. effects, the π-complex is systematically slightly more bound than the chemisorbed alkoxide complex, whereas mol. dynamics calcns. at 323 K yield an almost equal stability of both species. The carbenium ion was not obsd. during simulations at 323 K. The transformation from the π-complex to the chemisorbed complex is activated by a free energy in the range of 33-42 kJ/mol. Our observations yield unprecedented insights into the stability of elusive intermediates in zeolite catalysis, for which exptl. data are very hard to measure.
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  71. 71
    Bučko, T.; Benco, L.; Hafner, J.; Ángyán, J. G. Monomolecular cracking of propane over acidic chabazite: An ab initio molecular dynamics and transition path sampling study. J. Catal. 2011, 279, 220– 228,  DOI: 10.1016/j.jcat.2011.01.022
    Google Scholar
    71
    Monomolecular cracking of propane over acidic chabazite: An ab initio molecular dynamics and transition path sampling study
    Bucko, Tomas; Benco, Lubomir; Hafner, Juergen; Angyan, Janos G.
    Journal of Catalysis (2011), 279 (1), 220-228CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    The monomol. Haag-Dessau mechanism for propane cracking over acidic chabazite has been studied using dispersion-cor. periodic DFT calcns. in combination with ab initio mol. dynamics (AIMD) simulations, transition path sampling (TPS), and free-energy integrations. The AIMD simulations show that due to the weak specific interaction of the satd. mol. with Bronsted acid sites, the adsorption energy is considerably reduced at elevated temp. and that only a fraction of the mols. adsorbed within the zeolite is sufficiently close to the acid site to form a reactant complex for protonation. TPS shows that the preferred reaction mechanism is the protonation of a terminal Me group. The direct proton attack on the C-C bond between the Me and methylene groups is not excluded but occurs with lower probability. The intrinsic reaction parameters such as free energy and entropy of activation are detd. using thermodn. integration based on constrained mol. dynamics simulations.
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  72. 72
    Zimmerman, P. M.; Tranca, D. C.; Gomes, J.; Lambrecht, D. S.; Head-Gordon, M.; Bell, A. T. Ab Initio Simulations Reveal that Reaction Dynamics Strongly Affect Product Selectivity for the Cracking of Alkanes over H-MFI. J. Am. Chem. Soc. 2012, 134, 19468– 19476,  DOI: 10.1021/ja3089372
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    72
    Ab Initio Simulations Reveal that Reaction Dynamics Strongly Affect Product Selectivity for the Cracking of Alkanes over H-MFI
    Zimmerman, Paul M.; Tranca, Diana C.; Gomes, Joseph; Lambrecht, Daniel S.; Head-Gordon, Martin; Bell, Alexis T.
    Journal of the American Chemical Society (2012), 134 (47), 19468-19476CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Product selectivity of alkane cracking catalysis in the H-MFI zeolite is investigated using both static and dynamic first-principles quantum mechanics/mol. mechanics simulations. These simulations account for the electrostatic- and shape-selective interactions in the zeolite and provide enthalpic barriers that are closely comparable to expt. Cracking transition states for n-pentane lead to a metastable intermediate (a local min. with relatively small barriers to escape to deeper min.) where the proton is shared between two hydrocarbon fragments. The zeolite strongly stabilizes these carbocations compared to the gas phase, and the conversion of this intermediate to more stable species dets. the product selectivity. Static reaction pathways on the potential energy surface starting from the metastable intermediate include a variety of possible conversions into more stable products. One-picosecond quasiclassical trajectory simulations performed at 773 K indicate that dynamic paths are substantially more diverse than the potential energy paths. Vibrational motion that is dynamically sampled after the cracking transition state causes spilling of the metastable intermediate into a variety of different products. A nearly 10-fold change in the branching ratio between C2/C3 cracking channels is found upon inclusion of post-transition-state dynamics, relative to static electronic structure calcns. Agreement with expt. is improved by the same factor. Because dynamical effects occur soon after passing through the rate-limiting transition state, it is the dynamics, and not only the potential energy barriers, that det. the catalytic selectivity. This study suggests that selectivity in zeolite catalysis is detd. by high temp. pathways that differ significantly from 0 K potential surfaces.
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  73. 73
    Gounder, R.; Iglesia, E. Catalytic Consequences of Spatial Constraints and Acid Site Location for Monomolecular Alkane Activation on Zeolites. J. Am. Chem. Soc. 2009, 131, 1958– 1971,  DOI: 10.1021/ja808292c
    Google Scholar
    73
    Catalytic Consequences of Spatial Constraints and Acid Site Location for Monomolecular Alkane Activation on Zeolites
    Gounder, Rajamani; Iglesia, Enrique
    Journal of the American Chemical Society (2009), 131 (5), 1958-1971CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    The location of Bronsted acid sites within zeolite channels strongly influences reactivity because of the extent to which spatial constraints det. the stability of reactants and of cationic transition states relevant to alkane activation catalysis. Turnover rates for monomol. cracking and dehydrogenation of propane and n-butane differed among zeolites with varying channel structure (H-MFI, H-FER, H-MOR) and between OH groups within eight-membered ring (8-MR) side pockets and 12-MR main channels in H-MOR. Measured monomol. alkane activation barriers depended on catalyst and reactant properties, such as deprotonation enthalpies and proton affinities, resp., consistent with Born-Haber thermochem. cycles that define energy relations in acid catalysis. Monomol. alkane cracking and dehydrogenation turnovers occurred with strong preference on acid sites contained within smaller 8-MR pockets in H-MOR, while rates on sites located within 12-MR channels were much lower and often undetectable. This strong specificity reflects transition states that are confined only partially within 8-MR pockets; as a result, entropic gains compensate for enthalpic penalties caused by their incomplete containment to give a lower free energy for transition states within small 8-MR side pockets. These effects of entropy are stronger for dehydrogenation, with a later and looser transition state, than for cracking in the case of both propane and n-butane; therefore, selectivity can be tuned by the selective positioning or titrn. of OH groups within specific environments, the no. of which was assessed in H-MOR by rigorous deconvolution of their IR spectra. Specifically, cracking-to-dehydrogenation ratios for propane and n-butane were much smaller and terminal-to-central C-C bond cleavage ratios for n-butane were much larger on 8-MR than on 12-MR acid sites as a result of partial confinement, a concept previously considered phenomenol. as pore mouth catalysis. These marked effects of spatial constraints and of entropic factors on acid site reactivity and selectivity, also inferred for MFI from titrn. of OH groups by Na+, have not been previously proposed or recognized and appear to be unprecedented in hydrocarbon catalysis. These findings and their conceptual interpretations open opportunities for the design of microporous solids by the rational positioning of acid sites within specific channel locations and with predictable consequences for catalytic rates and selectivities.
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  74. 74
    Gounder, R.; Iglesia, E. Effects of Partial Confinement on the Specificity of Monomolecular Alkane Reactions for Acid Sites in Side Pockets of Mordenite. Angew. Chem., Int. Ed. 2010, 49, 808– 811,  DOI: 10.1002/anie.200905869
    Google Scholar
    74
    Effects of Partial Confinement on the Specificity of Monomolecular Alkane Reactions for Acid Sites in Side Pockets of Mordenite
    Gounder, Rajamani; Iglesia, Enrique
    Angewandte Chemie, International Edition (2010), 49 (4), 808-811, S808/1-S808/13CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Isobutane cracking has a stronger preference for reaction within eight-membered ring (8-MR) side pockets in mordenite zeolite (MOR) than does dehydrogenation, in sharp contrast with the trends for n-alkane reactions. Transition state energies are higher for isobutane cracking than for dehydrogenation, consistent with the less stable cations formed upon protonation of C-C bonds instead of the tertiary C-H bond in isobutane. As for monomol. n-alkane dehydrogenation, isobutane cracking shows a stronger preference for reaction on 8-MR acid sites than does dehydrogenation because it involves later and looser transition states, which benefit more strongly from entropy gains arising from partial confinement.
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  75. 75
    Sarazen, M. L.; Doskocil, E.; Iglesia, E. Catalysis on solid acids: Mechanism and catalyst descriptors in oligomerization reactions of light alkenes. J. Catal. 2016, 344, 553– 569,  DOI: 10.1016/j.jcat.2016.10.010
    Google Scholar
    75
    Catalysis on solid acids: Mechanism and catalyst descriptors in oligomerization reactions of light alkenes
    Sarazen, Michele L.; Doskocil, Eric; Iglesia, Enrique
    Journal of Catalysis (2016), 344 (), 553-569CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    This study addresses fundamental descriptions of confinement and acid strength effects on stability for transition states and intermediates involved in alkene oligomerization on solid acids. Kinetic and IR data and theor. treatments that account for dispersive interactions show that turnover rates (per H+) on aluminosilicates and heterosilicates with microporous voids (TON, MFI, BEA, FAU) and on mesoporous acids (amorphous silica-alumina, dispersed polyoxometalates) reflect the free energy of C-C bond formation transition states referenced to gaseous alkenes and bound alkene-derived precursors present at satn. coverages. These free energy barriers decrease as the size of confining voids decreases in aluminosilicates contg. acid sites of similar acid strength and approaches bimol. transition state (TS) sizes derived from d. functional theory (DFT) for propene and isobutene reactants. Such TS structures are preferentially stabilized over smaller bound precursors via contacts with the confining framework. These effects of size, typically based on heuristic geometric analogies, are described here instead by the dispersive component of DFT-derived energies for TS and intermediates, which bring together the effects of size and the shape, for different framework voids and TS and precursor structures derived from alkenes of different size; these org. moieties differ in "fit" within voids but also in their proton affinity, as a result of the ion-pair character of TS structures. The larger charge in TS structures relative to their alkene-derived precursors causes free energy barriers to decrease as conjugate anions become more stable in stronger acids. Consequently, oligomerization rate consts. decrease exponentially with increasing deprotonation energy on unconfined acid sites in polyoxometalates and silica-alumina and on confined sites within MFI frameworks with Al, Ga, Fe, or B heteroatoms. Reactivity descriptions based on geometry or acid strength are replaced by their more relevant energetic descriptors-van der Waals confinement energies, proton affinities of org. mols., and deprotonation energies-to account for reactivity, here for different reactants on diverse solid acids, but in general for acid catalysis.
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  76. 76
    Sarazen, M. L.; Iglesia, E. Stability of bound species during alkene reactions on solid acids. Proc. Natl. Acad. Sci. U. S. A. 2017, 114, E3900– E3908,  DOI: 10.1073/pnas.1619557114
    Google Scholar
    76
    Stability of bound species during alkene reactions on solid acids
    Sarazen, Michele L.; Iglesia, Enrique
    Proceedings of the National Academy of Sciences of the United States of America (2017), 114 (20), E3900-E3908CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)
    This study reports the thermodn. of bound species derived from ethene, propene, n-butene, and isobutene on solid acids with diverse strength and confining voids. D. functional theory (DFT) and kinetic data indicate that covalently bound alkoxides form C-C bonds in the kinetically relevant step for dimerization turnovers on protons within TON (0.57 nm) and MOR (0.67 nm) zeolitic channels and on stronger acids HPW (polyoxometalate clusters on silica). Turnover rates for mixed alkenes give relative alkoxide stabilities; the resp. adsorption consts. are obtained from in situ IR spectra. Tertiary alkoxides (from isobutene) within larger voids (MOR, HPW) are more stable than less substituted isomers but are destabilized within smaller concave environments (TON) because framework distortions are required to avoid steric repulsion. Adsorption consts. are similar on MOR and HPW for each alkoxide, indicating that binding is insensitive to acid strength for covalently bound species. DFT-derived formation free energies for alkoxides with different framework attachments and backbone length/structure agree with measurements when dispersion forces, which mediate stabilization by confinement in host-guest systems, are considered. Theory reveals previously unrecognized framework distortions that balance the C-O bond lengths required for covalency with host-guest distances that maximize van der Waals contacts. These distortions, reported here as changes in O-atom locations and dihedral angles, become stronger for larger, more substituted alkoxides. The thermodn. properties reported here for alkoxides and acid hosts differing in size and conjugate-anion stability are benchmarked against DFT-derived free energies; their details are essential to design host-guest pairs that direct alkoxide species toward specific products.
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  77. 77
    De Moor, B. A.; Reyniers, M. F.; Gobin, O. C.; Lercher, J. A.; Marin, G. B. Adsorption of C2–C8 n-Alkanes in Zeolites. J. Phys. Chem. C 2011, 115, 1204– 1219,  DOI: 10.1021/jp106536m
    Google Scholar
    77
    Adsorption of C2-C8 n-Alkanes in Zeolites
    De Moor, Bart A.; Reyniers, Marie-Francoise; Gobin, Oliver C.; Lercher, Johannes A.; Marin, Guy B.
    Journal of Physical Chemistry C (2011), 115 (4), 1204-1219CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    Adsorption of n-alkanes has been studied in the industrially relevant zeolites H-FAU, H-BEA, H-MOR, and H-ZSM-5 combining QM-Pot(MP2//B3LYP) with statistical thermodn. calcns. and assuming a mobile adsorbate. In H-ZSM-5, adsorption at the intersection site with the hydrocarbon chain extending in the straight channel (SC+I) as well as in the zigzag channel (ZC+I) has been studied. In addn., differential heats of adsorption and adsorption isotherms at temps. from 301 to 400 K of all C3-C6 n-alkane in H-ZSM-5 have been measured simultaneously via calorimetry and gravimetry. Calcd. adsorption enthalpies are independent of temp. and are virtually identical to the adsorption energies. The adsorption strength increases in the order H-FAU < H-BEA < H-MOR < H-ZSM-5 (SC+I) < H-ZSM-5 (ZC+I) and varies linearly with the carbon no. As compared to exptl. values, the calcd. adsorption strength is overestimated by some 2 kJ mol-1/CH2 in FAU up to some 4 kJ mol-1/CH2 in H-ZSM-5 suggesting that the QM-Pot(MP2//B3LYP) calcns. overestimate van der Waals stabilizing interactions and a correction term has been proposed. Adsorption entropy losses are independent of temp. and increase in the order H-FAU < H-BEA < H-MOR < H-ZSM-5 (SC+I) < H-ZSM-5 (ZC+I), according to the pore size of the zeolites. The calcd. adsorption entropies agree nicely with available exptl. results in all zeolites. QM-Pot(MP2//B3LYP) calcd. adsorption equil. coeffs. (using the cor. adsorption enthalpies) correspond relatively well to exptl. detd. values. Comparison of relative turnover frequencies with relative adsorption equil. coeffs. indicates that the variation of the equil. coeff. with the carbon no. or with the zeolite can only partly explain the obsd. reactivity differences in monomol. cracking of n-alkanes. In agreement with exptl. observations, our results indicate that the difference in reactivity of the n-alkanes for monomol. cracking in a given zeolite mainly originates from a difference in intrinsic monomol. cracking rate coeffs.
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  78. 78
    Nguyen, C. M.; De Moor, B. A.; Reyniers, M. F.; Marin, G. B. Isobutene Protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22. J. Phys. Chem. C 2012, 116, 18236– 18249,  DOI: 10.1021/jp304081k
    Google Scholar
    78
    Isobutene Protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22
    Nguyen, Cuong M.; De Moor, Bart A.; Reyniers, Marie-Francoise; Marin, Guy B.
    Journal of Physical Chemistry C (2012), 116 (34), 18236-18249CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    Kinetics and thermodn. of isobutene protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22 were studied at 300-800 K, combining PW91-D//PW91 periodic d. functional theory calcns. with statistical thermodn. At temps. relevant for industrial zeolite-catalyzed processes (500-800 K), the tert-Bu carbenium ion is more stable than the tert-butoxy in H-MOR, H-ZSM-5, and H-ZSM-22. Entropy contributions govern the std. Gibbs free energy stability of the chemisorbed intermediates. Due to the absence of a C-O covalent bond, formation of the tert-Bu carbenium ion is accompanied by a lower entropy loss and, consequently, has a higher stability than the tert-butoxy in H-MOR, H-ZSM-5, and H-ZSM-22. At 800 K, the protonation toward tert-butoxy in H-FAU, H-MOR, and H-ZSM-5 and to the tert-Bu carbenium ion in H-ZSM-22 is 5 to 7 orders of magnitude faster than the protonation toward isobutoxy. Among the four zeolites, the lowest activation energy is found in H-ZSM-22.
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  79. 79
    Bučko, T.; Hafner, J. The role of spatial constraints and entropy in the adsorption and transformation of hydrocarbons catalyzed by zeolites. J. Catal. 2015, 329, 32– 48,  DOI: 10.1016/j.jcat.2015.04.015
    Google Scholar
    79
    Role of spatial constraints and entropy in adsorption and transformation of hydrocarbon cracking catalyzed by zeolites
    Bucko, Tomas; Hafner, Jurgen
    Journal of Catalysis (2015), 329 (), 32-48CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
    The competing influences of enthalpy and entropy on the adsorption and transformation of hydrocarbon mols. in zeolites have been investigated using dispersion-cor. d.-functional theory in combination with advanced statistical-mech. techniques. At the example of propane in protonated mordenite, it is demonstrated that while enthalpy favors adsorption in the narrower side pockets (SP) due to the stronger interaction with the framework, the loss of entropy is smaller for mols. in the wider main channel (MC). At ambient and elevated temps., the free energy favors adsorption in the MC (in agreement with expt.) and diffusion to the SP is an activated process. On the other hand, the free energy of activation for monomol. cracking is lower for Bronsted acid (BA) sites in the SP, if the reactant is already located there. Cracking at a BA in the MC is a simple one-step reaction but as the SP is accessible to mols. only via the MC, cracking at a BA site in the SP is possible only after overcoming the barrier for diffusion from the MC to the SP. Thus, the difference in the free energies of adsorption in the MC and the SP increases the effective free-energy of activation for the reaction in SP and the reaction in the MC is favored. This result contradicts the interpretation of recent expts. on hydrocarbon transformations catalyzed by mordenite-contg. BA sites and Na+ counterions in varying proportions. This exptl. interpretation is based on the assumption that Na+ counterions preferentially replace BA sites located in the SP. This assumption has been critically examd. using ab-initio calcns. and found to be inconsistent with our theor. predictions. It is demonstrated that the exptl. obsd. decrease of the reaction rate with increasing Na+/H+ ratio arises from the strongly attractive nature of the Na+ counterions, which makes the approach of the reactant to the BA site more difficult and reduces the reaction rate. We suggest that our results on the competing influence of enthalpy and entropy arising from the confinement of the reactant in cavities of different diams. have general validity for the adsorption and acid-catalyzed reactions of hydrocarbon mols. in zeolites with a complex framework structure.
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  80. 80
    Janda, A.; Vlaisavljevich, B.; Lin, L. C.; Smit, B.; Bell, A. T. Effects of Zeolite Structural Confinement on Adsorption Thermodynamics and Reaction Kinetics for Monomolecular Cracking and Dehydrogenation of n-Butane. J. Am. Chem. Soc. 2016, 138, 4739– 4756,  DOI: 10.1021/jacs.5b11355
    Google Scholar
    80
    Effects of Zeolite Structural Confinement on Adsorption Thermodynamics and Reaction Kinetics for Monomolecular Cracking and Dehydrogenation of n-Butane
    Janda, Amber; Vlaisavljevich, Bess; Lin, Li-Chiang; Smit, Berend; Bell, Alexis T.
    Journal of the American Chemical Society (2016), 138 (14), 4739-4756CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    The effects of zeolite structure on the kinetics of n-butane monomol. cracking and dehydrogenation are investigated for eight zeolites differing in the topol. of channels and cages. Monte Carlo simulations are used to calc. enthalpy and entropy changes for adsorption (ΔHads-H+ and ΔSads-H+) of gas-phase alkanes onto Bronsted protons. These parameters are used to ext. intrinsic activation enthalpies (ΔH‡int), entropies (ΔS‡int), and rate coeffs. (kint) from measured data. As ΔSads-H+ decreases (i.e., as confinement increases), ΔH‡int and ΔS‡int for terminal cracking and dehydrogenation decrease for a given channel topol. These results, together with pos. values obsd. for ΔS‡int, indicate that the transition states for these reactions resemble products. For central cracking (an earlier transition state), ΔH‡int is relatively const., while ΔS‡int increases as ΔSads-H+ decreases because less entropy is lost upon protonation of the alkane. Concurrently, selectivities to terminal cracking and dehydrogenation decrease relative to central cracking because ΔS‡int decreases for the former reactions. Depending on channel topol., changes in the measured rate coeffs. (kapp) with confinement are driven by changes in kint or by changes in the adsorption equil. const. (Kads-H+). Values of ΔS‡int and ΔH‡int are pos. correlated, consistent with weaker interactions between the zeolite and transition state and with the greater freedom of movement of product fragments within more spacious pores. These results differ from earlier reports that ΔH‡int and ΔS‡int are structure-insensitive and that kapp is dominated by Kads-H+. They also suggest that ΔSads-H+ is a meaningful descriptor of confinement for zeolites having similar channel topologies.
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  81. 81
    Dutta Chowdhury, A.; Gascon, J. The Curious Case of Ketene in Zeolite Chemistry and Catalysis. Angew. Chem., Int. Ed. 2018, 57, 14982– 14985,  DOI: 10.1002/anie.201808480
    Google Scholar
    There is no corresponding record for this reference.
  82. 82
    Kuei, C. K.; Lee, M. D. Hydrogenation of Carbon Dioxide by Hybrid Catalysts, Direct Synthesis of Aromatics from Carbon Dioxide and Hydrogen. Can. J. Chem. Eng. 1991, 69, 347– 354,  DOI: 10.1002/cjce.5450690142
    Google Scholar
    82
    Hydrogenation of carbon dioxide by hybrid catalysts, direct synthesis of aromatics from carbon dioxide and hydrogen
    Kuei, Chi Kung; Lee, Min Dar
    Canadian Journal of Chemical Engineering (1991), 69 (1), 347-54CODEN: CJCEA7; ISSN:0008-4034.
    Direct synthesis of aroms. from CO2 hydrogenation was investigated in a single stage reactor by using hybrid catalysts composed of Fe catalysts and HZSM-5 zeolite. CO2 was first converted to CO by the reverse water gas shift reaction, followed by the hydrogenation of CO to hydrocarbons on Fe catalyst, and finally the hydrocarbons were converted to aroms. in HZSM-5. Under the operating conditions of 350°, 2100 kPa, and CO2/H = 1/2, the max. arom. selectivity obtained was 22% with a CO2 conversion of 38% by using fused Fe catalyst combined with the zeolite. Together with the kinetic studies, thermodn. anal. of the CO2 hydrogenation was also conducted. Unlike Fischer Tropsch synthesis, the formation of hydrocarbons from CO2 may not be thermodynamically favored at higher temps.
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  83. 83
    Fujiwara, M.; Ando, H.; Tanaka, M.; Souma, Y. Hydrogenation of Carbon Dioxide over Cu-Zn-Chromate/Zeolite Composite Catalyst: The Effects of Reaction Behavior of Alkenes on Hydrocarbon Synthesis. Appl. Catal., A 1995, 130, 105– 116,  DOI: 10.1016/0926-860X(95)00108-5
    Google Scholar
    83
    Hydrogenation of carbon dioxide over Cu-Zn-chromate/zeolite composite catalyst: The effects of reaction behavior of alkenes on hydrocarbon synthesis
    Fujiwara, Masahiro; Ando, Hisanori; Tanaka, Mutsuo; Souma, Yoshie
    Applied Catalysis, A: General (1995), 130 (1), 105-16CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
    The hydrogenation of carbon dioxide was studied using composite catalysts comprised of Cu-Zn-chromate and HY zeolite. These composite catalysts enabled the reaction combining methanol synthesis and methanol-to-gasoline reaction, and achieved the formation of ethylene and propene as the first example of the composite catalysts. The addn. of alk. metals, esp. cesium, to Cu-Zn-chromate enhanced the selectivities of those alkenes. The influences of the reaction pressure and the space velocity on the prodn. of alkenes show that alkanes are obtained by the hydrogenation of the corresponding alkenes. The composite catalysts producing alkenes in high selectivity afforded heavier hydrocarbons preferentially. These results indicate that the hydrogenation of alkenes inhibits the carbon homologation of alkenes to result in the predominant formation of the corresponding lighter alkanes. From these observations, methanol synthesis catalysts used for the composite catalysts are required to be effective for methanol synthesis at high temp. (over 300°) and to bear the low activity of the hydrogenation of alkenes.
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    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXnvFSqt7s%253D&md5=abd58fead57069d70cf1834c964d45e6
  84. 84
    Fujiwara, M.; Kieffer, R.; Ando, H.; Xu, Q.; Souma, Y. Change of Catalytic Properties of FeZnO/Zeolite Composite Catalyst in the Hydrogenation of Carbon Dioxide. Appl. Catal., A 1997, 154, 87– 101,  DOI: 10.1016/S0926-860X(96)00360-2
    Google Scholar
    84
    Change of catalytic properties of Fe-ZnO/zeolite composite catalyst in the hydrogenation of carbon dioxide
    Fujiwara, Masahiro; Kieffer, Roger; Ando, Hisanori; Xu, Qiang; Souma, Yoshie
    Applied Catalysis, A: General (1997), 154 (1-2), 87-101CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
    The hydrogenation of carbon dioxide was examd. using the composite catalysts which were obtained by the phys. mixing of Fe-ZnO and HY zeolite. Fe-ZnO was a typical F-T (Fischer-Tropsch) catalyst and Fe-ZnO/HY is a composite catalyst which is able to induce a combined methanol synthesis and MTG (Methanol-to-Gasoline) reaction. To study these unique catalytic behaviors of Fe-ZnO/HY, the adsorption and the dissocn. of carbon monoxide on Fe-ZnO as well as TPR measurements were carried out. Fe-ZnO is able to produce hydrocarbons by F-T reaction and methanol. In the absence of zeolite, Fe-ZnO exerts its ability for F-T reaction. However, HY diminishes the activity for F-T reaction and hydrocarbons were obtained via methanol formed over the modified Fe-ZnO.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXisleiurY%253D&md5=857453a538dddd07684646329ada6cb2
  85. 85
    Kim, H.; Choi, D. H.; Nam, S. S.; Choi, M. J.; Lee, K. W. The Selective Synthesis of Lower Olefins (C2 - C4) by the CO2 Hydrogenation over Iron Catalysts Promoted with Potassium and Supported on Ion Exchanged (H, K) Zeolite-Y. Stud. Surf. Sci. Catal. 1998, 114, 407– 410,  DOI: 10.1016/S0167-2991(98)80782-9
    Google Scholar
    85
    The selective synthesis of lower olefins (C2 - C4) by the CO2 hydrogenation over iron catalysts promoted with potassium and supported on ion exchanged (H, K) zeolite-Y
    Kim, Ho; Choi, Dae-Ho; Nam, Sang-Sung; Choi, Myung-Jae; Lee, Kyu-Wan
    Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 407-410CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
    Selective for lower olefins (C2-C4) in carbon dioxide hydrogenation over zeolite-supported iron catalysts promoted with potassium is increased when potassium-exchanged zeolite is used. however, hydrogen-exchanged zeolite decreased surface basicity and increased methane formation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjt1ajsL8%253D&md5=1265c031a770eed9001b94c943bf3f78
  86. 86
    Xu, Q.; He, D.; Fujiwara, M.; Tanaka, M.; Matsumura, Y.; Souma, Y.; Ando, H.; Yamanaka, H. Hydrogenation of Carbon Dioxide over Fe-Cu-Na/Zeolite Composite Catalysts. Stud. Surf. Sci. Catal. 1998, 114, 423– 426,  DOI: 10.1016/S0167-2991(98)80786-6
    Google Scholar
    86
    Hydrogenation of carbon dioxide over Fe-Cu-Na/zeolite composite catalysts
    Xu, Qiang; He, Dehua; Fujiwara, Masahiro; Tanaka, Mutsuo; Matsumura, Yasuyuki; Souma, Yoshie; Ando, Hisanori; Yamanaka, Hiroshi
    Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 423-426CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
    Phys. mixts. of sodium-rich, iron-based catalysts with zeolites greatly improved their activity for carbon dioxide hydrogenation to hydrocarbons at 250°. Sodium migration from the surface of the iron-based catalyst to the zeolite via solid-solid reaction accounts for this change of catalytic activity.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjt1ajsLs%253D&md5=9d1ceb366992784881b6c16d55e4ab68
  87. 87
    Tan, Y.; Fujiwara, M.; Ando, H.; Xu, Q.; Souma, Y. Selective Formation of iso-Butane from Carbon Dioxide and Hydrogen over Composite Catalysts. Stud. Surf. Sci. Catal. 1998, 114, 435– 438,  DOI: 10.1016/S0167-2991(98)80789-1
    Google Scholar
    87
    Selective formation of iso-butane from carbon dioxide and hydrogen over composite catalysts
    Tan, Yisheng; Fujiwara, Masahiro; Ando, Hisanori; Xu, Qiang; Souma, Yoshie
    Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 435-438CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
    The hydrogenation of carbon dioxide over composite catalysts comprised of Fe-Zn-M (M = Cr, Al, Ga, or Zr) and HY zeolite gives isobutane with high selectivities. The mechanism of isobutane formation combines the methanol synthesis reaction and the methanol-to-gasoline reaction, and olefins are important intermediates for isobutane formation. Isobutane can be dehydrogenated to isobutylene for MTBE prodn.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjt1ajsLY%253D&md5=47fcfb8f07a16431ab8164d028fcb0cd
  88. 88
    Nam, S. S.; Kim, H.; Kishan, G.; Choi, M. J.; Lee, K. W. Catalytic Conversion of Carbon Dioxide into Hydrocarbons over Iron Supported on Alkali Ion-Exchanged Y-Zeolite Catalysts. Appl. Catal., A 1999, 179, 155– 163,  DOI: 10.1016/S0926-860X(98)00322-6
    Google Scholar
    88
    Catalytic conversion of carbon dioxide into hydrocarbons over iron supported on alkali ion-exchanged Y-zeolite catalysts
    Nam, Sang-Sung; Kim, Ho; Kishan, Gurram; Choi, Myoung-Jae; Lee, Kyu-Wan
    Applied Catalysis, A: General (1999), 179 (1-2), 155-163CODEN: ACAGE4; ISSN:0926-860X. (Elsevier Science B.V.)
    Iron supported on HY-zeolite and on alkali metal (Li, Na, K, Rb) ion exchanged Y-zeolite prepd. by impregnation technique have been characterized by XRD, AAS, BET surface area, CO2 chemisorption, temp. programmed redn. (TPR) and temp. programmed decarburization (TPDC) techniques. These catalysts have been tested for catalytic activity for CO2 hydrogenation to hydrocarbons. The XRD patterns of Fe/HY catalysts indicate the formation of Fe2O3 monolayer at 17 wt.% Fe. It is found that alkali metals exchanged in zeolite-Y increase the basicity of the catalyst surface, which influence the activity and selectivity of the catalysts in CO2 hydrogenation. The TPR profile of Fe2O3 catalyst is obsd. to contain only two peaks, corresponding to the redn. of Fe2O3 to Fe0 through Fe3O4. However, the TPR profiles of Fe/MY catalysts contain three peaks, which indicate the formation of iron phase through FeO phase. The peak corresponding to the redn. of Fe3O4 to FeO is obsd. to increase in intensity and in area and to shift to higher temps. in the order: H<Li<Na<K<Rb. The peaks in the TPDC profiles of the catalysts, which represent the redn. of carbide structures, are also obsd. to increase in area and to shift to higher temps. The CO2 conversion and the total hydrocarbon selectivity are found to vary over a narrow range, whereas the selectivities of C2-C4 olefins and C5+ hydrocarbons are very much influenced by the alkali metal present in the catalyst. The activities of the catalysts are correlated with physico-chem. characteristics of the catalysts.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXhsVegurw%253D&md5=00f27dd7162677e90299b7bc7d9cb3c9
  89. 89
    Nam, S. S.; Kishan, G.; Lee, M. W.; Choi, M. J.; Lee, K. W. Selective Synthesis of C2-C4 Olefins and C5+ Hydrocarbons over Unpromoted and Cerium-Promoted Iron Catalysts Supported on Ion Exchanged (H, K) Zeolite-Y. J. Chem. Res., Synop. 1999, 5, 344– 345,  DOI: 10.1039/a900457b
    Google Scholar
    There is no corresponding record for this reference.
  90. 90
    Li, Z.; Wang, J.; Qu, Y.; Liu, H.; Tang, C.; Miao, S.; Feng, Z.; An, H.; Li, C. Highly Selective Conversion of Carbon Dioxide to Lower Olefins. ACS Catal. 2017, 7, 8544– 8548,  DOI: 10.1021/acscatal.7b03251
    Google Scholar
    90
    Highly Selective Conversion of Carbon Dioxide to Lower Olefins
    Li, Zelong; Wang, Jijie; Qu, Yuanzhi; Liu, Hailong; Tang, Chizhou; Miao, Shu; Feng, Zhaochi; An, Hongyu; Li, Can
    ACS Catalysis (2017), 7 (12), 8544-8548CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
    Conversion of CO2 to value-added chems. has been a long-standing objective, and direct hydrogenation of CO2 to lower olefins is highly desirable but still challenging. Herein, we report a selective conversion of CO2 to lower olefins through CO2 hydrogenation over a ZnZrO/SAPO tandem catalyst fabricated with a ZnO-ZrO2 solid soln. and a Zn-modified SAPO-34 zeolite, which can achieve a selectivity for lower olefins as high as 80-90% among hydrocarbon products. This is realized on the basis of the dual functions of the tandem catalyst: hydrogenation of CO2 on the ZnO-ZrO2 solid soln. and lower olefins prodn. on the SAPO zeolite. The thermodn. and kinetic coupling between the tandem reactions enable the highly efficient conversion of CO2 to lower olefins. Furthermore, this catalyst is stable toward thermal and sulfur treatments, showing potential industrial application.
    >> More from SciFinder ®
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  3. Lu Qin, Sen Wang, Sheng Fan, Mei Dong, Zhangfeng Qin, Jianguo Wang, Weibin Fan. Selective Hydrogenation of CO2 into Ethene and Propene over a GaZrOx/H-SAPO-17 Composite Catalyst. ACS Catalysis 2023, 13 (18) , 11919-11933. https://doi.org/10.1021/acscatal.3c01785
  4. Yanbing Li, Yingluo He, Kensei Fujihara, Yongqiang Gu, Weizhe Gao, Shuhei Yasuda, Guohui Yang, Noritatsu Tsubaki. Directly Converting CO2 to Light Hydrocarbons on a FeCoAl Prussian Blue Analogue-Based Core–Shell Catalyst via Fischer–Tropsch Synthesis. ACS Catalysis 2023, 13 (18) , 12174-12185. https://doi.org/10.1021/acscatal.3c02034
  5. Veronique Van Speybroeck, Massimo Bocus, Pieter Cnudde, Louis Vanduyfhuys. Operando Modeling of Zeolite-Catalyzed Reactions Using First-Principles Molecular Dynamics Simulations. ACS Catalysis 2023, 13 (17) , 11455-11493. https://doi.org/10.1021/acscatal.3c01945
  6. Qisheng Jiang, Guiyao Song, Yangzhou Zhai, Chonghao Chen, Zihao Wang, Huimin Yuan, Zhixiang Zhang, Dianhua Liu. Selective Hydrogenation of CO2 to Aromatics over Composite Catalyst Comprising NaZnFe and Polyethylene Glycol-Modified HZSM-5 with Intra- and Intercrystalline Mesoporous Structure. Industrial & Engineering Chemistry Research 2023, 62 (23) , 9188-9200. https://doi.org/10.1021/acs.iecr.3c00915
  7. Konstantijn Tom Rommens, Mark Saeys. Molecular Views on Fischer–Tropsch Synthesis. Chemical Reviews 2023, 123 (9) , 5798-5858. https://doi.org/10.1021/acs.chemrev.2c00508
  8. Iman Nezam, Wei Zhou, Dhrumil R. Shah, Maxim P. Bukhovko, Madelyn R. Ball, Gabriel S. Gusmão, Andrew J. Medford, Christopher W. Jones. Role of Catalyst Domain Size in the Hydrogenation of CO2 to Aromatics over ZnZrOx/ZSM-5 Catalysts. The Journal of Physical Chemistry C 2023, 127 (13) , 6356-6370. https://doi.org/10.1021/acs.jpcc.3c01306
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  10. Xuan Gong, Yiru Ye, Abhishek Dutta Chowdhury. Evaluating the Role of Descriptor- and Spectator-Type Reaction Intermediates During the Early Phases of Zeolite Catalysis. ACS Catalysis 2022, 12 (24) , 15463-15500. https://doi.org/10.1021/acscatal.2c04600
  11. Zhiyan Si, Linkai Wang, Yu Han, Jiafeng Yu, Qingjie Ge, Chunyang Zeng, Jian Sun. Synthesis of Alkene and Ethanol in CO2 Hydrogenation on a Highly Active Sputtering CuNaFe Catalyst. ACS Sustainable Chemistry & Engineering 2022, 10 (45) , 14972-14979. https://doi.org/10.1021/acssuschemeng.2c05450
  12. Yang Zhang, Pan Gao, Feng Jiao, Yuxiang Chen, Yilun Ding, Guangjin Hou, Xiulian Pan, Xinhe Bao. Chemistry of Ketene Transformation to Gasoline Catalyzed by H-SAPO-11. Journal of the American Chemical Society 2022, 144 (40) , 18251-18258. https://doi.org/10.1021/jacs.2c03478
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  25. Sudipta De, Abhay Dokania, Adrian Ramirez, Jorge Gascon. Advances in the Design of Heterogeneous Catalysts and Thermocatalytic Processes for CO2 Utilization. ACS Catalysis 2020, 10 (23) , 14147-14185. https://doi.org/10.1021/acscatal.0c04273
  26. Yu Han, Chuanyan Fang, Xuewei Ji, Jian Wei, Qingjie Ge, Jian Sun. Interfacing with Carbonaceous Potassium Promoters Boosts Catalytic CO2 Hydrogenation of Iron. ACS Catalysis 2020, 10 (20) , 12098-12108. https://doi.org/10.1021/acscatal.0c03215
  27. Guiyao Song, Minzhe Li, Peikun Yan, Muhammad Asif Nawaz, Dianhua Liu. High Conversion to Aromatics via CO2-FT over a CO-Reduced Cu-Fe2O3 Catalyst Integrated with HZSM-5. ACS Catalysis 2020, 10 (19) , 11268-11279. https://doi.org/10.1021/acscatal.0c02722
  28. Yajing Wang, Weiteng Zhan, Zhijie Chen, Jianmin Chen, Xingang Li, Yingwei Li. Advanced 3D Hollow-Out ZnZrO@C Combined with Hierarchical Zeolite for Highly Active and Selective CO Hydrogenation to Aromatics. ACS Catalysis 2020, 10 (13) , 7177-7187. https://doi.org/10.1021/acscatal.0c01418
  29. Yuebing Xu, Ting Wang, Chengming Shi, Bing Liu, Feng Jiang, Xiaohao Liu. Experimental Investigation on the Two-Sided Effect of Acidic HZSM-5 on the Catalytic Performance of Composite Fe-Based Fischer–Tropsch Catalysts and HZSM-5 Zeolite in the Production of Aromatics from CO2/H2. Industrial & Engineering Chemistry Research 2020, 59 (18) , 8581-8591. https://doi.org/10.1021/acs.iecr.0c00992
  30. Pieter Cnudde, Ruben Demuynck, Steven Vandenbrande, Michel Waroquier, German Sastre, Veronique Van Speybroeck. Light Olefin Diffusion during the MTO Process on H-SAPO-34: A Complex Interplay of Molecular Factors. Journal of the American Chemical Society 2020, 142 (13) , 6007-6017. https://doi.org/10.1021/jacs.9b10249
  31. N. A. Krans, J. L. Weber, W. van den Bosch, J. Zečević, P. E. de Jongh, K. P. de Jong. Influence of Promotion on the Growth of Anchored Colloidal Iron Oxide Nanoparticles during Synthesis Gas Conversion. ACS Catalysis 2020, 10 (3) , 1913-1922. https://doi.org/10.1021/acscatal.9b04380
  32. Cheng Zhou, Jiaqing Shi, Wei Zhou, Kang Cheng, Qinghong Zhang, Jincan Kang, Ye Wang. Highly Active ZnO-ZrO2 Aerogels Integrated with H-ZSM-5 for Aromatics Synthesis from Carbon Dioxide. ACS Catalysis 2020, 10 (1) , 302-310. https://doi.org/10.1021/acscatal.9b04309
  33. Shunwu Wang, Tijun Wu, Jun Lin, Jing Tian, Yushan Ji, Yan Pei, Shirun Yan, Minghua Qiao, Hualong Xu, Baoning Zong. FeK on 3D Graphene–Zeolite Tandem Catalyst with High Efficiency and Versatility in Direct CO2 Conversion to Aromatics. ACS Sustainable Chemistry & Engineering 2019, 7 (21) , 17825-17833. https://doi.org/10.1021/acssuschemeng.9b04328
  34. Cederick Cyril Amoo, Joshua Iseoluwa Orege, Qingjie Ge, Jian Sun. Translating clean liquid fuels synthesis with low aromatics over NaFe@C/HZSM-22 directly in CO2 hydrogenation. Applied Catalysis B: Environmental 2024, 340 , 123193. https://doi.org/10.1016/j.apcatb.2023.123193
  35. David P. Serrano, Gabriele Centi, Paul A. Diddams, Jiří Čejka. Outlooks for zeolite catalysts in a low-carbon scenario. Catalysis Today 2024, 426 , 114365. https://doi.org/10.1016/j.cattod.2023.114365
  36. Jie Zhu, Minchen Mu, Yi Liu, Miao Zhang, Guanghui Zhang, Zening Cheng, Ben Hang Yin, Alex C.K. Yip, Chunshan Song, Xinwen Guo. Unveiling the promoting effect of potassium on the structural evolution of iron catalysts during CO2 hydrogenation. Chemical Engineering Science 2023, 282 , 119228. https://doi.org/10.1016/j.ces.2023.119228
  37. Haoxi Jiang, Yifei Xu, Guangshen Li, Guochao Yang, Minhua Zhang, Xingtian Shu, Lingtao Wang. Proof-of-Concept of ketene chemistry: Experimental and theoretical calculations on the synthesis of p-methoxyacetophenone from ethenone with anisole. Molecular Catalysis 2023, 551 , 113633. https://doi.org/10.1016/j.mcat.2023.113633
  38. Eyhab Ali, Mohammed Abdulkadhim Sayah, Ahmed Abd Al-Sattar Dawood, Abdul-hameed M Hamoody, Zainab Jamal Hamoodah, Montather F. Ramadan, Hussein Abdullah Abbas, Ahmed Alawadi, Ali Alsalamy, Rathab Abbass. CO2 reduction reaction on Sc-doped nanocages as catalysts. Journal of Molecular Modeling 2023, 29 (12) https://doi.org/10.1007/s00894-023-05776-1
  39. Nicholas S. Featherstone, Eric van Steen. Meta-analysis of the thermo-catalytic hydrogenation of CO₂. Catalysis Today 2023, 423 , 113951. https://doi.org/10.1016/j.cattod.2022.11.012
  40. XiLan Li, Jing Wang, XiaoLi Wei. Investigation of Possible Mechanisms of CO2 Reduction Reaction on Ni Doped Carbon Nanocage and Ni Doped Silicon Nanocage as Effective Catalysts. Silicon 2023, 15 (17) , 7639-7646. https://doi.org/10.1007/s12633-023-02617-x
  41. Kun Liu, Adrian Ramirez, Xin Zhang, Mustafa Çağlayan, Xuan Gong, Jorge Gascon, Abhishek Dutta Chowdhury. Interplay Between Particle Size and Hierarchy of Zeolite ZSM‐5 During the CO 2 ‐to‐aromatics Process. ChemSusChem 2023, 16 (19) https://doi.org/10.1002/cssc.202300608
  42. Fatima Mahnaz, Violet Dunlap, Ryan Helmer, Siddhesh Shirish Borkar, Ricardo Navar, Xiaokun Yang, Manish Shetty. Selective Valorization of CO 2 towards Valuable Hydrocarbons through Methanol‐mediated Tandem Catalysis. ChemCatChem 2023, 15 (17) https://doi.org/10.1002/cctc.202300402
  43. Pieter Cnudde, Michel Waroquier, Veronique Van Speybroeck. Universal descriptors for zeolite topology and acidity to predict the stability of butene cracking intermediates. Catalysis Science & Technology 2023, 13 (16) , 4857-4872. https://doi.org/10.1039/D3CY00642E
  44. Wenhang Wang, Ruosong He, Yang Wang, Meng Li, Jianxin Liu, Jiaming Liang, Shuhei Yasuda, Qiang Liu, Mingbo Wu, Noritatsu Tsubaki. Boosting Methanol‐Mediated CO 2 Hydrogenation into Aromatics by Synergistically Tailoring Oxygen Vacancy and Acid Site Properties of Multifunctional Catalyst. Chemistry – A European Journal 2023, 29 (40) https://doi.org/10.1002/chem.202301135
  45. Xin Shang, Guodong Liu, Xiong Su, Yanqiang Huang, Tao Zhang. A review of the recent progress on direct heterogeneous catalytic CO 2 hydrogenation to gasoline-range hydrocarbons. EES Catalysis 2023, 1 (4) , 353-368. https://doi.org/10.1039/D3EY00026E
  46. Linkai Wang, Yu Han, Jian Wei, Qingjie Ge, Shijian Lu, Yanpeng Mao, Jian Sun. Dynamic confinement catalysis in Fe-based CO2 hydrogenation to light olefins. Applied Catalysis B: Environmental 2023, 328 , 122506. https://doi.org/10.1016/j.apcatb.2023.122506
  47. Lijun Zhang, Weizhe Gao, Fan Wang, Chengwei Wang, Jiaming Liang, Xiaoyu Guo, Yingluo He, Guohui Yang, Noritatsu Tsubaki. Highly selective synthesis of light aromatics from CO2 by chromium-doped ZrO2 aerogels in tandem with HZSM-5@SiO2 catalyst. Applied Catalysis B: Environmental 2023, 328 , 122535. https://doi.org/10.1016/j.apcatb.2023.122535
  48. Xudong Fang, Bin Li, Hongchao Liu, Mingguan Xie, Zhiyang Chen, Leilei Yang, Jingfeng Han, Wenliang Zhu, Zhongmin Liu. High carbon utilization for CO2 conversion with chloromethane to aromatics over acidic zeolite catalyst. Chem Catalysis 2023, 3 (7) , 100689. https://doi.org/10.1016/j.checat.2023.100689
  49. Yuebing Xu, Bing Liu, Feng Jiang, Xiaohao Liu. Carbon Monoxide and Carbon Dioxide for Aromatics Production. 2023, 533-553. https://doi.org/10.1002/9783527827992.ch19
  50. Lisheng Guo, Xiaoyu Guo, Yinglue He, Noritatsu Tsubaki. CO 2 heterogeneous hydrogenation to carbon-based fuels: recent key developments and perspectives. Journal of Materials Chemistry A 2023, 11 (22) , 11637-11669. https://doi.org/10.1039/D3TA01025B
  51. Yi Fen Zhu, Bingqiao Xie, Rose Amal, Emma C. Lovell, Jason Scott. Light‐Enhanced Conversion of CO 2 to Light Olefins: Basis in Thermal Catalysis, Current Progress, and Future Prospects. Small Structures 2023, 4 (6) https://doi.org/10.1002/sstr.202200285
  52. Qingxin Yang, Elizaveta A. Fedorova, Sergey A. Petrov, Jana Weiss, Henrik Lund, Andrey S. Skrypnik, Carsten Robert Kreyenschulte, Victor Yu. Bychkov, Alexander A. Matvienko, Angelika Brueckner, Evgenii V. Kondratenko. Activity and selectivity descriptors for iron carbides in CO2 hydrogenation. Applied Catalysis B: Environmental 2023, 327 , 122450. https://doi.org/10.1016/j.apcatb.2023.122450
  53. Kambiz Sadeghi, Yukwon Jeon, Jongchul Seo. Roadmap to the sustainable synthesis of polymers: From the perspective of CO2 upcycling. Progress in Materials Science 2023, 135 , 101103. https://doi.org/10.1016/j.pmatsci.2023.101103
  54. Peng Lu, Xiaoning Chang, Wenjia Yu, Qianwen Hu, Kime Mala Ali, Chuang Xing, Ce Du, Zhixiang Yang, Shuyao Chen. Synergistic effects of ZnO–ZrO2@SAPO-34 core-shell catalyst in catalyzing CO2 hydrogenation for the synthesis of light olefins. Renewable Energy 2023, 209 , 546-557. https://doi.org/10.1016/j.renene.2023.03.111
  55. C. Coffano, A. Porta, C.G. Visconti, F. Rabino, G. Franzoni, B. Picutti, L. Lietti. One-pot lower olefins production from CO2 hydrogenation. Catalysis Today 2023, 418 , 114133. https://doi.org/10.1016/j.cattod.2023.114133
  56. Yang Cheng, Yong Chen, Shuxian Zhang, Xiaoting Wu, Chide Chen, Xin Shi, Ming Qing, Jifan Li, Chun-Ling Liu, Wen-Sheng Dong. High-yield production of aromatics over CuFeO 2 /hierarchical HZSM-5 via CO 2 Fischer–Tropsch synthesis. Green Chemistry 2023, 25 (9) , 3570-3584. https://doi.org/10.1039/D2GC04896E
  57. Ali A. Al-Qadri, Galal A. Nasser, Haruna Adamu, Oki Muraza, Tawfik A. Saleh. CO2 utilization in syngas conversion to dimethyl ether and aromatics: Roles and challenges of zeolites-based catalysts. Journal of Energy Chemistry 2023, 79 , 418-449. https://doi.org/10.1016/j.jechem.2022.12.037
  58. Kalagotla Sai Chandana, Swetha Karka, Manleen Kaur Gujral, Reddi Kamesh, Anirban Roy. Machine learning aided catalyst activity modelling and design for direct conversion of CO2 to lower olefins. Journal of Environmental Chemical Engineering 2023, 11 (2) , 109555. https://doi.org/10.1016/j.jece.2023.109555
  59. Alexandra Velty, Avelino Corma. Advanced zeolite and ordered mesoporous silica-based catalysts for the conversion of CO 2 to chemicals and fuels. Chemical Society Reviews 2023, 52 (5) , 1773-1946. https://doi.org/10.1039/D2CS00456A
  60. Zhixuan Hua, Yingju Yang, Jing Liu. Direct hydrogenation of carbon dioxide to value-added aromatics. Coordination Chemistry Reviews 2023, 478 , 214982. https://doi.org/10.1016/j.ccr.2022.214982
  61. M. Sunil Kumar, M.S. Alphin, P. Senthil Kumar, S. Raja. A review on zeolite catalyst for deNOx performance in ammonia–selective catalytic reduction. Fuel 2023, 334 , 126828. https://doi.org/10.1016/j.fuel.2022.126828
  62. Qiang Liu, Jie Ding, Ruonan Wang, Qin Zhong. FeZnK/SAPO-34 Catalyst for Efficient Conversion of CO2 to Light Olefins. Catalysis Letters 2023, 153 (1) , 54-61. https://doi.org/10.1007/s10562-021-03863-7
  63. Unalome Wetwatana Hartley, Praveen Kumar Murugesan. Dual functional nano zeolites for CO2 capture and conversion. 2023, 309-332. https://doi.org/10.1016/B978-0-323-89851-5.00016-0
  64. Yongjun Jiang, Kangzhou Wang, Yuan Wang, Zhihao Liu, Xinhua Gao, Jianli Zhang, Qingxiang Ma, Subing Fan, Tian-Sheng Zhao, Min Yao. Recent advances in thermocatalytic hydrogenation of carbon dioxide to light olefins and liquid fuels via modified Fischer-Tropsch pathway. Journal of CO2 Utilization 2023, 67 , 102321. https://doi.org/10.1016/j.jcou.2022.102321
  65. Wenyu Zhang, Sen Wang, Shujia Guo, Zhangfeng Qin, Mei Dong, Weibin Fan, Jianguo Wang. Ga CrO /H-SAPO-34(F), a highly efficient bifunctional catalyst for the direct conversion of CO2 into ethene and propene. Fuel 2022, 329 , 125475. https://doi.org/10.1016/j.fuel.2022.125475
  66. Saikat Dutta, Navya Subray Bhat, Harshitha N. Anchan. Nanocatalysis for Renewable Aromatics. 2022, 61-90. https://doi.org/10.1002/9781119772057.ch2
  67. Jyoti Gahtori, Vivek Kumar Shrivastaw, Ankur Bordoloi. Advances in Direct Thermocatalytic CO 2 Conversion to Chemicals and Hydrocarbons. 2022, 155-193. https://doi.org/10.1002/9781119772057.ch21
  68. A. Ateka, P. Rodriguez-Vega, J. Ereña, A.T. Aguayo, J. Bilbao. Kinetic modeling and reactor design of the direct synthesis of dimethyl ether for CO2 valorization. A review. Fuel 2022, 327 , 125148. https://doi.org/10.1016/j.fuel.2022.125148
  69. Keye Qin, Yong Men, Shuang Liu, Jinguo Wang, Zhuping Li, Dandan Tian, Tianle Shi, Wei An, Xiaoli Pan, Lin Li. Direct conversion of carbon dioxide to liquid hydrocarbons over K-modified CoFeOx/zeolite multifunctional catalysts. Journal of CO2 Utilization 2022, 65 , 102208. https://doi.org/10.1016/j.jcou.2022.102208
  70. Sen Wang, Li Zhang, Pengfei Wang, Weiyong Jiao, Zhangfeng Qin, Mei Dong, Jianguo Wang, Unni Olsbye, Weibin Fan. Highly selective hydrogenation of CO2 to propane over GaZrOx/H-SSZ-13 composite. Nature Catalysis 2022, 5 (11) , 1038-1050. https://doi.org/10.1038/s41929-022-00871-7
  71. Lingrui Cui, Cao Liu, Benzhen Yao, Peter P. Edwards, Tiancun Xiao, Fahai Cao. A review of catalytic hydrogenation of carbon dioxide: From waste to hydrocarbons. Frontiers in Chemistry 2022, 10 https://doi.org/10.3389/fchem.2022.1037997
  72. Na Guo, Jinyao Zhang, Luxiang Jiang, Dengtai Wang, Zuwu Wang. Highly efficient and selective Ru and Ce modified ZSM-5 catalysts for catalytic oxidation of toluene. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2022, 651 , 129709. https://doi.org/10.1016/j.colsurfa.2022.129709
  73. Wenyu Zhang, Sen Wang, Shujia Guo, Zhangfeng Qin, Mei Dong, Jianguo Wang, Weibin Fan. Effective conversion of CO2 into light olefins along with generation of low amounts of CO. Journal of Catalysis 2022, 413 , 923-933. https://doi.org/10.1016/j.jcat.2022.07.041
  74. Heng Zhao, Chunyang Zeng, Noritatsu Tsubaki. A mini review on recent advances in thermocatalytic hydrogenation of carbon dioxide to value-added chemicals and fuels. Resources Chemicals and Materials 2022, 1 (3-4) , 230-248. https://doi.org/10.1016/j.recm.2022.07.002
  75. Marlon Tavares, Gisele Westphalen, João Monnerat Araujo Ribeiro de Almeida, Pedro Nothaft Romano, Eduardo Falabella Sousa-Aguiar. Modified fischer-tropsch synthesis: A review of highly selective catalysts for yielding olefins and higher hydrocarbons. Frontiers in Nanotechnology 2022, 4 https://doi.org/10.3389/fnano.2022.978358
  76. A. Ateka, P. Rodriguez-Vega, J. Ereña, A.T. Aguayo, J. Bilbao. A review on the valorization of CO2. Focusing on the thermodynamics and catalyst design studies of the direct synthesis of dimethyl ether. Fuel Processing Technology 2022, 233 , 107310. https://doi.org/10.1016/j.fuproc.2022.107310
  77. A. Portillo, A. Ateka, J. Ereña, J. Bilbao, A.T. Aguayo. Role of Zr loading into In2O3 catalysts for the direct conversion of CO2/CO mixtures into light olefins. Journal of Environmental Management 2022, 316 , 115329. https://doi.org/10.1016/j.jenvman.2022.115329
  78. Qiang Wang, Kehao Hu, Ruxing Gao, Leiyu Zhang, Lei Wang, Chundong Zhang. Hydrogenation of Carbon Dioxide to Value-Added Liquid Fuels and Aromatics over Fe-Based Catalysts Based on the Fischer–Tropsch Synthesis Route. Atmosphere 2022, 13 (8) , 1238. https://doi.org/10.3390/atmos13081238
  79. Malayil Gopalan Sibi, Deepak Verma, Jaehoon Kim. Direct conversion of CO 2 into aromatics over multifunctional heterogeneous catalysts. Catalysis Reviews 2022, 11 , 1-60. https://doi.org/10.1080/01614940.2022.2099058
  80. Jian Sun, Lisheng Guo. CO 2 Reduction to Fuels and Chemicals. 2022, 425-458. https://doi.org/10.1002/9783527815906.ch12
  81. Yahya Gambo, Sagir Adamu, Rahima A. Lucky, Mohammed S. Ba-Shammakh, Mohammad M. Hossain. Tandem catalysis: A sustainable alternative for direct hydrogenation of CO2 to light olefins. Applied Catalysis A: General 2022, 641 , 118658. https://doi.org/10.1016/j.apcata.2022.118658
  82. Aleksandr Fedorov, David Linke. Data analysis of CO2 hydrogenation catalysts for hydrocarbon production. Journal of CO2 Utilization 2022, 61 , 102034. https://doi.org/10.1016/j.jcou.2022.102034
  83. Yi Ji, Pan Gao, Zhenchao Zhao, Dong Xiao, Qiao Han, Hongyu Chen, Ke Gong, Kuizhi Chen, Xiuwen Han, Xinhe Bao, Guangjin Hou. Oxygenate-based routes regulate syngas conversion over oxide–zeolite bifunctional catalysts. Nature Catalysis 2022, 5 (7) , 594-604. https://doi.org/10.1038/s41929-022-00806-2
  84. Abhay Dokania, Adrian Ramirez, Genrikh Shterk, Jose Luis Cerrillo, Jorge Gascon. Modifying the Hydrogenation Activity of Zeolite Beta for Enhancing the Yield and Selectivity for Fuel‐Range Alkanes from Carbon Dioxide. ChemPlusChem 2022, 87 (6) https://doi.org/10.1002/cplu.202200177
  85. Qingxin Yang, Vita A. Kondratenko, Sergey A. Petrov, Dmitry E. Doronkin, Erisa Saraçi, Henrik Lund, Aleks Arinchtein, Ralph Kraehnert, Andrey S. Skrypnik, Alexander A. Matvienko, Evgenii V. Kondratenko. Bestimmung von Performance‐Deskriptoren für die CO 2 ‐Hydrierung an alkalimetallpromotierten Katalysatoren auf Eisenbasis. Angewandte Chemie 2022, 134 (22) https://doi.org/10.1002/ange.202116517
  86. Qingxin Yang, Vita A. Kondratenko, Sergey A. Petrov, Dmitry E. Doronkin, Erisa Saraçi, Henrik Lund, Aleks Arinchtein, Ralph Kraehnert, Andrey S. Skrypnik, Alexander A. Matvienko, Evgenii V. Kondratenko. Identifying Performance Descriptors in CO 2 Hydrogenation over Iron‐Based Catalysts Promoted with Alkali Metals. Angewandte Chemie International Edition 2022, 61 (22) https://doi.org/10.1002/anie.202116517
  87. Heuntae Jo, Muhammad Kashif Khan, Muhammad Irshad, Malik Waqar Arshad, Seok Ki Kim, Jaehoon Kim. Unraveling the role of cobalt in the direct conversion of CO2 to high-yield liquid fuels and lube base oil. Applied Catalysis B: Environmental 2022, 305 , 121041. https://doi.org/10.1016/j.apcatb.2021.121041
  88. Sen Wang, Li Zhang, Pengfei Wang, Xingchen Liu, Yanyan Chen, Zhangfeng Qin, Mei Dong, Jianguo Wang, Lin He, Unni Olsbye, Weibin Fan. Highly effective conversion of CO2 into light olefins abundant in ethene. Chem 2022, 8 (5) , 1376-1394. https://doi.org/10.1016/j.chempr.2022.01.004
  89. Wenyu Zhang, Sen Wang, Shujia Guo, Zhangfeng Qin, Mei Dong, Jianguo Wang, Weibin Fan. Effective conversion of CO 2 into light olefins over a bifunctional catalyst consisting of La-modified ZnZrO x oxide and acidic zeolite. Catalysis Science & Technology 2022, 12 (8) , 2566-2577. https://doi.org/10.1039/D2CY00210H
  90. Weizhe Gao, Lisheng Guo, Qinming Wu, Chengwei Wang, Xiaoyu Guo, Yingluo He, Peipei Zhang, Guohui Yang, Guangbo Liu, Jinhu Wu, Noritatsu Tsubaki. Capsule-like zeolite catalyst fabricated by solvent-free strategy for para-Xylene formation from CO2 hydrogenation. Applied Catalysis B: Environmental 2022, 303 , 120906. https://doi.org/10.1016/j.apcatb.2021.120906
  91. Feng Sha, Xinyi Liu, Shan Tang, Jijie Wang, Can Li. Hydrogenation of CO 2 to Chemicals with Green Hydrogen. 2022, 1073-1184. https://doi.org/10.1002/9783527831883.ch25
  92. Masahiro Fujiwara. Highly Selective Production of Aromatic Hydrocarbons by CO 2 Hydrogenation over Fe-Zn Oxide + H-ZSM-5 Composite Catalyst. Bulletin of the Chemical Society of Japan 2022, 95 (3) , 389-399. https://doi.org/10.1246/bcsj.20210421
  93. Grandprix T.M. Kadja, Moh. Mualliful Ilmi, Noerma J. Azhari, Munawar Khalil, Adroid T.N. Fajar, Subagjo, I.G.B.N. Makertihartha, Melia L. Gunawan, Carolus B. Rasrendra, I.G. Wenten. Recent advances on the nanoporous catalysts for the generation of renewable fuels. Journal of Materials Research and Technology 2022, 17 , 3277-3336. https://doi.org/10.1016/j.jmrt.2022.02.033
  94. Wenjun Zhang, Ding Ma, Javier Pérez-Ramírez, Zupeng Chen. Recent Progress in Materials Exploration for Thermocatalytic, Photocatalytic, and Integrated Photothermocatalytic CO 2 ‐to‐Fuel Conversion. Advanced Energy and Sustainability Research 2022, 3 (2) https://doi.org/10.1002/aesr.202100169
  95. Malayil Gopalan Sibi, Muhammad Kashif Khan, Deepak Verma, Wonjoong Yoon, Jaehoon Kim. High-yield synthesis of BTEX over Na–FeAlOx/Zn–HZSM-5@SiO2 by direct CO2 conversion and identification of surface intermediates. Applied Catalysis B: Environmental 2022, 301 , 120813. https://doi.org/10.1016/j.apcatb.2021.120813
  96. Zhenzhou Zhang, Yangyang Liu, Lingyu Jia, Chao Sun, Baojian Chen, Rui Liu, Yisheng Tan, Weifeng Tu. Effects of the reducing gas atmosphere on performance of FeCeNa catalyst for the hydrogenation of CO2 to olefins. Chemical Engineering Journal 2022, 428 , 131388. https://doi.org/10.1016/j.cej.2021.131388
  97. Manleen Kaur Gujral, Reddi Kamesh, Anirban Roy. Machine Learning Based Catalyst Modelling for Direct Conversion of Co2 to Lower Olefins. SSRN Electronic Journal 2022, 59 https://doi.org/10.2139/ssrn.4046595
  98. Robert Franz, Donato Pinto, Evgeny A. Uslamin, Atsushi Urakawa, Evgeny A. Pidko. Impact of Promoter Addition on the Regeneration of Ni/Al 2 O 3 Dry Reforming Catalysts. ChemCatChem 2021, 13 (23) , 5034-5046. https://doi.org/10.1002/cctc.202101080
  99. Qiming Sun, Ning Wang, Jihong Yu. Advances in Catalytic Applications of Zeolite‐Supported Metal Catalysts. Advanced Materials 2021, 33 (51) https://doi.org/10.1002/adma.202104442
  100. Ruwei Yao, Jian Wei, Qingjie Ge, Jing Xu, Yu Han, Qingxiang Ma, Hengyong Xu, Jian Sun. Monometallic iron catalysts with synergistic Na and S for higher alcohols synthesis via CO2 hydrogenation. Applied Catalysis B: Environmental 2021, 298 , 120556. https://doi.org/10.1016/j.apcatb.2021.120556
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  • Abstract

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    Figure 1

    Figure 1. Characterization of the bifunctional Fe2O3@KO2/zeolite material. (A) XRD patterns of the commercial zeolites and the fresh and spent stand-alone Fe catalyst. (B) TEM image of the stand-alone Fe catalyst activated under reaction conditions. K (C) and Fe (D) elemental mapping of the stand-alone Fe catalyst activated under reaction conditions.

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    Figure 2

    Figure 2. Catalytic performance of the bifunctional Fe2O3@KO2/zeolite system. (A) Product distribution of the Fe2O3@KO2/ZSM-5 and Fe2O3@KO2 catalysts after 50 h TOS. (B) Product distribution of the Fe2O3@KO2/MOR and Fe2O3@KO2 catalysts after 50 h TOS. (C) Stability of the Fe2O3@KO2/ZSM-5 bifunctional catalyst during 150 h TOS. (D) Stability of the Fe2O3@KO2/MOR bifunctional catalyst during 150 h TOS. Reaction conditions: 375 °C, 30 bar, H2/CO2 = 3, and 5000 mL·g–1·h–1.

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    Figure 3

    Figure 3. Effect of zeolite properties on the catalytic performance of the Fe2O3@KO2/ZSM-5 bifunctional system. (A) Effect of the SiO2/Al2O3 ratio on the aromatic selectivity. (B) Molar relationship between aromatics and the paraffins produced for the different SiO2/Al2O3 ratios tested. Reaction conditions: 375 °C, 30 bar, H2/CO2 = 3, 5000 mL·g–1·h–1, and 50 h TOS.

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    Figure 4

    Figure 4. 2D MAS 1H–13C cross-polarization HETCOR ssNMR correlations of identified zeolite MOR trapped molecular scaffolds: olefinic/vinylic (in light green), aliphatic (in blue), and carbonyl (in purple). (A) Spectra obtained on the post-reacted MOR after the hydrogenation of carbon dioxide over Fe2O3@KO2/MOR for 50 h. Herein, dipolar cross-polarization was used to polarize carbons in this correlation spectrum. Zooms of (B) aliphatic and (C) carbonyl regions are displayed separately (number of scans = 3504).

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    Figure 5

    Figure 5. 2D MAS 1H–13C cross-polarization HETCOR ssNMR correlations. (A) Spectra obtained on the post-reacted ZSM-5 after the hydrogenation of carbon dioxide over Fe2O3@KO2/ZSM-5 for 50 h. (B) Identified zeolite ZSM-5-trapped molecular scaffolds: olefinic/vinylic (in light green), mono-aromatics (in green), poly-aromatics (in brown), and aliphatic (in blue) (number of scans = 2496).

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    Figure 6

    Figure 6. Adsorption free energy at 350 °C for 1-, 2-, 3-, and 4-nonene and 2-nonyl carbenium ion in H-ZSM-5, H-MOR-1, and H-MOR-2 with the empty framework and the respective n-nonene in the gas phase as reference state. For the carbenium ion, gas-phase 1-nonene and the empty framework are chosen as reference (level of theory: PBE-D3).

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    Figure 7

    Figure 7. Sampling percentage of the π-complex, vdW-complex, and carbocation intermediates during the 100 ps MD simulations of the linear C9 species at 350 °C in (A) H-ZSM-5, (B) H-MOR-1, and (C) H-MOR-2 (level of theory: revPBE-D3/DZVP-GTH).

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    Figure 8

    Figure 8. Free energy profile for the adsorption (from static calculations, level of theory: PBE-D3) and protonation (from umbrella sampling, level of theory: revPBE-D3/TZVP-GTH) of 1-nonene π-complex into 2-nonyl carbenium ion in H-ZSM-5 (blue) and H-MOR-1 (red) at 350 °C, with the empty framework and 1-nonene in gas phase as reference states.

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    Figure 9

    Figure 9. Proposed reaction pathways of the Fe2O3@KO2/zeolite-catalyzed hydrogenation of CO2 to light olefins and aromatics. (A) CO2 hydrogenation pathway on the stand-alone Fe2O3@KO2 catalyst. (B) CO incorporation pathway on MOR and ZMS-5. (C) Aromatization pathway on ZSM-5.

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  • References

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    This article references 90 other publications.

    1. 1
      WMO. The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2016, Greenhouse Gas Bulletin (GHG Bulletin) No. 13; World Meteorological Organization, 2017.
      Google Scholar
      There is no corresponding record for this reference.
    2. 2
      Global Carbon Budget 2018. https://www.globalcarbonproject.org/carbonbudget (accessed May 25, 2019).
      Google Scholar
      There is no corresponding record for this reference.
    3. 3
      Alper, E.; Orhan, O. Y. CO2 utilization: Developments in conversion processes. Petroleum 2017, 3, 109– 126,  DOI: 10.1016/j.petlm.2016.11.003
      Google Scholar
      There is no corresponding record for this reference.
    4. 4
      Álvarez, A.; Bansode, A.; Urakawa, A.; Bavykina, A. V.; Wezendonk, T. A.; Makkee, M.; Gascon, J.; Kapteijn, F. Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Catalyzed CO2 Hydrogenation Processes. Chem. Rev. 2017, 117, 9804– 9838,  DOI: 10.1021/acs.chemrev.6b00816
      Google Scholar
      4
      Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Processes
      Alvarez, Andrea; Bansode, Atul; Urakawa, Atsushi; Bavykina, Anastasiya V.; Wezendonk, Tim A.; Makkee, Michiel; Gascon, Jorge; Kapteijn, Freek
      Chemical Reviews (Washington, DC, United States) (2017), 117 (14), 9804-9838CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. The recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to formate/formic acid, methanol, and di-Me ether are thoroughly reviewed, with special emphasis on thermodn. and catalyst design considerations. After introducing the main motivation for the development of such processes, we first summarize the most important aspects of CO2 capture and green routes to product H2. Once the scene in terms of feedstocks is introduced, we carefully summarize the state of the art in the development of heterogeneous catalysts for these important hydrogenation reactions. Finally, in an attempt to give an order of magnitude regarding CO2 valorization, we critically assess economical aspects of the prodn. of methanol and DME and outline future research and development directions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVKhu77L&md5=d50d9b311a6c8390d863664837c2fdac
    5. 5
      Centi, G.; Quadrelli, E. A.; Perathoner, S. Catalysis for CO2 conversion: a key technology for rapid introduction of renewable energy in the value chain of chemical industries. Energy Environ. Sci. 2013, 6, 1711– 1731,  DOI: 10.1039/c3ee00056g
      Google Scholar
      5
      Catalysis for CO2 conversion: a key technology for rapid introduction of renewable energy in the value chain of chemical industries
      Centi, Gabriele; Quadrelli, Elsje Alessandra; Perathoner, Siglinda
      Energy & Environmental Science (2013), 6 (6), 1711-1731CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)
      A review. Replacement of part of the fossil fuel consumption by renewable energy, in particular in the chem. industry, is a central strategy for resource and energy efficiency. This perspective will show that CO2 is the key mol. to proceed effectively in this direction. The routes, opportunities and barriers in increasing the share of renewable energy by using CO2 reaction and their impact on the chem. and energy value chains are discussed after introducing the general aspects of this topic evidencing the tight integration between the CO2 use and renewable energy insertion in the value chain of the process industry. The focus of this perspective article is on the catalytic aspects of the chemistries involved, with an anal. of the state-of-the-art, perspectives and targets to be developed. The reactions discussed are the prodn. of short-chain olefins (ethylene, propylene) from CO2, and the conversion of carbon dioxide to syngas, formic acid, methanol and di-Me ether, hydrocarbons via Fischer-Tropsch synthesis and methane. The relevance of availability, cost and environmental footprints of H2 prodn. routes using renewable energies is addressed. The final part discusses the possible scenario for CO2 as an intermediary for the incorporation of renewable energy in the process industry, with a concise road-map for catalysis needs and barriers to reach this goal.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnvFyrsbY%253D&md5=da0ecd251533100c9c8359aab13e8e3b
    6. 6
      Dokania, A.; Ramirez, A.; Bavykina, B.; Gascon, J. Heterogeneous Catalysis for the Valorization of CO2: Role of Bifunctional Processes in the Production of Chemicals. ACS Energy Lett. 2019, 4, 167– 179,  DOI: 10.1021/acsenergylett.8b01910
      Google Scholar
      6
      Heterogeneous Catalysis for the Valorization of CO2: Role of Bifunctional Processes in the Production of Chemicals
      Dokania, Abhay; Ramirez, Adrian; Bavykina, Anastasiya; Gascon, Jorge
      ACS Energy Letters (2019), 4 (1), 167-176CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)
      A review is given. CO2 is an abundant C feedstock, and there exists a sustained interest in methods for its utilization. At the moment, several routes that rely on the use of renewable energy for the valorization of CO2 are being considered, with a strong emphasis on fully electrocatalytic routes. Here, we highlight the role that heterogeneous catalysis may play in hybrid processes in which H is obtained via electrolysis and CO2 is valorized in a 2nd, dark step. Targeting high selectivity to value-added products (olefins and aroms.), we cover CO2-to-chems. routes that involve cascade multifunctional processes. In doing so, we highlight the main advantages of this approach along with the most important challenges and remaining questions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlWhtLfN&md5=3f73641a8da53aa63a34fac1b2414fe6
    7. 7
      Gao, P.; Dang, S.; Li, S.; Bu, X.; Liu, Z.; Qiu, M.; Yang, C.; Wang, H.; Zhong, L.; Han, Y.; Liu, Q.; Wei, W.; Sun, Y. Direct Production of Lower Olefins from CO2 Conversion via Bifunctional Catalysis. ACS Catal. 2018, 8, 571– 578,  DOI: 10.1021/acscatal.7b02649
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      7
      Direct Production of Lower Olefins from CO2 Conversion via Bifunctional Catalysis
      Gao, Peng; Dang, Shanshan; Li, Shenggang; Bu, Xianni; Liu, Ziyu; Qiu, Minghuang; Yang, Chengguang; Wang, Hui; Zhong, Liangshu; Han, Yong; Liu, Qiang; Wei, Wei; Sun, Yuhan
      ACS Catalysis (2018), 8 (1), 571-578CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      Direct conversion of carbon dioxide (CO2) into lower olefins (C2=-C4=), generally referring to ethylene, propylene, and butylene, is highly attractive as a sustainable prodn. route for its great significance in greenhouse gas control and fossil fuel substitution, but such a route always tends to be low in selectivity toward olefins. Here we present a bifunctional catalysis process that offers C2=-C4= selectivity as high as 80% and C2-C4 selectivity around 93% at more than 35% CO2 conversion. This is achieved by a bifunctional catalyst composed of indium-zirconium composite oxide and SAPO-34 zeolite, which is responsible for CO2 activation and selective C-C coupling, resp. We demonstrate that both the precise control of oxygen vacancies on the oxide surface and the integration manner of the components are crucial in the direct prodn. of lower olefins from CO2 hydrogenation. No obvious deactivation is obsd. over 150 h, indicating a promising potential for industrial application.
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    8. 8
      Wei, J.; Ge, Q.; Yao, R.; Wen, Z.; Fang, C.; Guo, L.; Xu, H.; Sun, J. Directly converting CO2 into a gasoline fuel. Nat. Commun. 2017, 8, 15174,  DOI: 10.1038/ncomms15174
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      8
      Directly converting CO2 into a gasoline fuel
      Wei Jian; Ge Qingjie; Yao Ruwei; Wen Zhiyong; Fang Chuanyan; Guo Lisheng; Xu Hengyong; Sun Jian; Wei Jian; Yao Ruwei; Wen Zhiyong; Guo Lisheng
      Nature communications (2017), 8 (), 15174 ISSN:.
      The direct production of liquid fuels from CO2 hydrogenation has attracted enormous interest for its significant roles in mitigating CO2 emissions and reducing dependence on petrochemicals. Here we report a highly efficient, stable and multifunctional Na-Fe3O4/HZSM-5 catalyst, which can directly convert CO2 to gasoline-range (C5-C11) hydrocarbons with selectivity up to 78% of all hydrocarbons while only 4% methane at a CO2 conversion of 22% under industrial relevant conditions. It is achieved by a multifunctional catalyst providing three types of active sites (Fe3O4, Fe5C2 and acid sites), which cooperatively catalyse a tandem reaction. More significantly, the appropriate proximity of three types of active sites plays a crucial role in the successive and synergetic catalytic conversion of CO2 to gasoline. The multifunctional catalyst, exhibiting a remarkable stability for 1,000 h on stream, definitely has the potential to be a promising industrial catalyst for CO2 utilization to liquid fuels.
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    9. 9
      Ramirez, A.; Gevers, L.; Bavykina, A.; Ould-Chikh, S.; Gascon, J. Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins. ACS Catal. 2018, 8, 9174– 9182,  DOI: 10.1021/acscatal.8b02892
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      9
      Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins
      Ramirez, Adrian; Gevers, Lieven; Bavykina, Anastasiya; Ould-Chikh, Samy; Gascon, Jorge
      ACS Catalysis (2018), 8 (10), 9174-9182CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      We report the synthesis of a highly active, selective, and stable catalyst for the hydrogenation of CO2 to short chain olefins in one single step by using a metal org. framework as catalyst precursor. By studying the promotion of the resulting Fe(41 wt. %)-carbon composites with different elements (Cu, Mo, Li, Na, K, Mg, Ca, Zn, Ni, Co, Mn, Fe, Pt, and Rh), we have found that only K is able to enhance olefin selectivity. Further catalyst optimization in terms of promoter loading results in catalysts displaying unprecedented C2-C4 olefin space time yields of 33.6 mmol·gcat-1·h-1 at XCO2 = 40%, 320 °C, 30 bar, H2/CO2 = 3, and 24 000 mL·g-1·h-1. Extensive characterization demonstrates that K promotion affects catalytic performance by (i) promoting a good balance between the different Fe active phases playing a role in CO2 hydrogenation, namely, iron oxide and iron carbides and by (ii) increasing CO2 and CO uptake while decreasing H2 affinity, interactions responsible for boosting olefin selectivity.
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    10. 10
      Rahimi, N.; Karimzadeh, R. Catalytic Cracking of Hydrocarbons over Modified ZSM-5 Zeolites to Produce Light Olefins: A Review. Appl. Catal., A 2011, 398, 1– 17,  DOI: 10.1016/j.apcata.2011.03.009
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      10
      Catalytic cracking of hydrocarbons over modified ZSM-5 zeolites to produce light olefins: A review
      Rahimi, Nazi; Karimzadeh, Ramin
      Applied Catalysis, A: General (2011), 398 (1-2), 1-17CODEN: ACAGE4; ISSN:0926-860X. (Elsevier B.V.)
      A review. Steam cracking of hydrocarbons has been the major source of light olefins for more than half a century. The recent studies have reported that ethylene and propylene can also be produced through the cracking of hydrocarbons over modified ZSM-5 zeolites in a considerable amt. This paper highlights the important current ideas about acid-catalyzed hydrocarbon cracking that has resulted in high yield of ethylene and propylene. Light olefin prodn. via catalytic cracking of various industrial feedstocks, ranging from heavy hydrocarbons to ethane, over modified ZSM-5 zeolites, has been reviewed in the present paper. Furthermore, the influence of various employed promoters, i.e., alkali and alk. earth, transition, rare earth elements, and phosphorus, on the chem. properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed. Moreover, the influences of different factors, including the zeolite acidity, Si/Al ratio and the temp., on the light olefin prodn. and the reaction scheme have been specified. The role of incorporated element in the catalytic cracking mechanism is also summarized.
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    11. 11
      Jadhav, S. G.; Vaidya, P. D.; Bhanage, B. M.; Joshi, J. B. Catalytic Carbon Dioxide Hydrogenation to Methanol: A Review of Recent Studies. Chem. Eng. Res. Des. 2014, 92, 2557– 2567,  DOI: 10.1016/j.cherd.2014.03.005
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      11
      Catalytic carbon dioxide hydrogenation to methanol: A review of recent studies
      Jadhav, Suhas G.; Vaidya, Prakash D.; Bhanage, Bhalchandra M.; Joshi, Jyeshtharaj B.
      Chemical Engineering Research and Design (2014), 92 (11), 2557-2567CODEN: CERDEE; ISSN:1744-3563. (Elsevier B.V.)
      A review. Methanol demand was continuously increasing in the chem. and energy industries. It was com. produced from synthesis gas (CO + CO2 + H2) using CuO/ZnO/Al2O3 catalysts. Today, much effort was being put on the development of technologies for its prodn. from carbon dioxide (CO2). In this way, the Greenhouse effect might be mitigated. Over the years, several useful works on CO2 hydrogenation to methanol had been reported in the literature. In this article, we present a comprehensive overview of all the recent studies published during the past decade. Various aspects on this reaction system (such as thermodn. considerations, innovations in catalysts, influences of reaction variables, overall catalyst performance, reaction mechanism and kinetics, and recent technol. advances) were described in detail. The major challenges confronting methanol prodn. from CO2 were considered. By now, such a discussion was still missing, and we intend to close this gap in this paper.
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    12. 12
      Yarulina, I.; De Wispelaere, K.; Bailleul, S.; Goetze, J.; Radersma, M.; Abou-Hamad, E.; Vollmer, I.; Goesten, M.; Mezari, B.; Hensen, E. J. M.; Martínez-Espín, J. S.; Morten, M.; Mitchell, S.; Perez-Ramirez, J.; Olsbye, O.; Weckhuysen, B. M.; Van Speybroeck, V.; Kapteijn, F.; Gascon, J. Structure-Performance Descriptors and the Role of Lewis Acidity in the Methanol-to-Propylene Process. Nat. Chem. 2018, 10, 804– 812,  DOI: 10.1038/s41557-018-0081-0
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      12
      Structure-performance descriptors and the role of Lewis acidity in the methanol-to-propylene process
      Yarulina, Irina; De Wispelaere, Kristof; Bailleul, Simon; Goetze, Joris; Radersma, Mike; Abou-Hamad, Edy; Vollmer, Ina; Goesten, Maarten; Mezari, Brahim; Hensen, Emiel J. M.; Martinez-Espin, Juan S.; Morten, Magnus; Mitchell, Sharon; Perez-Ramirez, Javier; Olsbye, Unni; Weckhuysen, Bert M.; Van Speybroeck, Veronique; Kapteijn, Freek; Gascon, Jorge
      Nature Chemistry (2018), 10 (8), 804-812CODEN: NCAHBB; ISSN:1755-4330. (Nature Research)
      The combination of well-defined acid sites, shape-selective properties and outstanding stability places zeolites among the most practically relevant heterogeneous catalysts. The development of structure-performance descriptors for processes that they catalyze has been a matter of intense debate, both in industry and academia, and the direct conversion of methanol to olefins is a prototypical system in which various catalytic functions contribute to the overall performance. Propylene selectivity and resistance to coking are the two most important parameters in developing new methanol-to-olefin catalysts. Here, we present a systematic investigation on the effect of acidity on the performance of the zeolite 'ZSM-5' for the prodn. of propylene. Our results demonstrate that the isolation of Bronsted acid sites is key to the selective formation of propylene. Also, the introduction of Lewis acid sites prevents the formation of coke, hence drastically increasing catalyst lifetime.
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    13. 13
      Yarulina, I.; Dutta Chowdhury, A.; Meirer, F.; Weckhuysen, B. M.; Gascon, J. Recent Trends and Fundamental insights in the Methanol-to-Hydrocarbons Process. Nat. Catal. 2018, 1, 398– 411,  DOI: 10.1038/s41929-018-0078-5
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      13
      Recent trends and fundamental insights in the methanol-to-hydrocarbons process
      Yarulina, Irina; Chowdhury, Abhishek Dutta; Meirer, Florian; Weckhuysen, Bert M.; Gascon, Jorge
      Nature Catalysis (2018), 1 (6), 398-411CODEN: NCAACP; ISSN:2520-1158. (Nature Research)
      The prodn. of high-demand chem. commodities such as ethylene and propylene (methanol-to-olefins), hydrocarbons (methanol-to-hydrocarbons), gasoline (methanol-to-gasoline) and aroms. (methanol-to-aroms.) from methanol-obtainable from alternative feedstocks, such as carbon dioxide, biomass, waste or natural gas through the intermediate formation of synthesis gas-has been central to research in both academia and industry. Although discovered in the late 1970s, this catalytic technol. has only been industrially implemented over the past decade, with a no. of large com. plants already operating in Asia. However, as is the case for other technologies, industrial maturity is not synonymous with full understanding. For this reason, research is still intense and a no. of important discoveries have been reported over the last few years. In this review, we summarize the most recent advances in mechanistic understanding-including direct C-C bond formation during the induction period and the promotional effect of zeolite topol. and acidity on the alkene cycle-and correlate these insights to practical aspects in terms of catalyst design and engineering.
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    14. 14
      Batchu, R.; Galvita, V. V.; Alexopoulos, K.; Van der Borght, K.; Poelman, H.; Reyniers, M.-F.; Marin, G. B. Role of Intermediates in Reaction Pathways from Ethene to Hydrocarbons over H-ZSM-5. Appl. Catal., A 2017, 538, 207– 220,  DOI: 10.1016/j.apcata.2017.03.013
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      14
      Role of intermediates in reaction pathways from ethene to hydrocarbons over H-ZSM-5
      Batchu, Rakesh; Galvita, Vladimir V.; Alexopoulos, Konstantinos; Van der Borght, Kristof; Poelman, Hilde; Reyniers, Marie-Francoise; Marin, Guy B.
      Applied Catalysis, A: General (2017), 538 (), 207-220CODEN: ACAGE4; ISSN:0926-860X. (Elsevier B.V.)
      Insight in ethene to hydrocarbon transformation over a H-ZSM-5 catalyst was obtained by temporal anal. of (TAP) in the temp. range 598-698 K with pulses of higher olefins, dienes, cyclodienes and aroms. Pulses of propene, 1-butene and 1-hexene allowed to identify the cracking routes from ethene oligomerization products. When pulsing benzene or ethylbenzene, only accumulation of aroms. occurred. In-situ temp. programmed desorption (TPD) expts. after pulsing identified aroms. as long-lived surface species. The role of intermediates was assessed by pre-adsorption of the different feeds before pulsing ethene, in so-called pump-probe expts. Butene enhanced propene formation, while all other olefins favored butene prodn. via aliph. surface intermediates. The latter were also intermediates in the conversion of hexadiene to butene and aroms., while cyclohexadiene was converted to propene and aroms. via arom. surface intermediates. In contrast to ethylbenzene pulses alone, aroms. alkylation participated towards light olefin prodn. via sidechain/paring mechanisms. Isotope expts. of 13C2H4 over a catalyst cocked during continuous flow expts. with 12C only showed scrambling in both propene and butene products, stressing the role of long-lived arom. surface intermediates.
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    15. 15
      Guisnet, M.; Gnep, N. S. Mechanism of Short-Chain Alkane Transformation over Protonic Zeolites. Alkylation, Disproportionation and Aromatization. Appl. Catal., A 1996, 146, 33– 64,  DOI: 10.1016/0926-860X(96)00282-7
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      15
      Mechanism of short-chain alkane transformation over protonic zeolites. Alkylation, disproportionation and aromatization
      Guisnet, M.; Gnep, N. S.
      Applied Catalysis, A: General (1996), 146 (1), 33-64CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
      A review with 105 refs. on the mechanism of alkane activation on zeolites. The influence of pore structure and acidity of the protonic zeolites on their activity and selectivity is discussed.
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    16. 16
      Gao, J.; Jia, C.; Liu, B. Direct and Selective Hydrogenation of CO2 to Ethylene and Propene by Bifunctional Catalysts. Catal. Sci. Technol. 2017, 7, 5602– 5607,  DOI: 10.1039/C7CY01549F
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      16
      Direct and selective hydrogenation of CO2 to ethylene and propene by bifunctional catalysts
      Gao, Jiajian; Jia, Chunmiao; Liu, Bin
      Catalysis Science & Technology (2017), 7 (23), 5602-5607CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)
      Redn. of CO2 by H2 produced from renewable electricity on a large scale would benefit both carbon recycling as well as H2 storage and transport. Among the various CO2 hydrogenation reaction products, light olefins, such as ethylene and propylene, are very important intermediates in the chem. industry. However, very efficient catalytic systems that are able to drive CO2 hydrogenation reactions selectively to make olefins do not exist although the reactions are thermodynamically favorable. In this study, we demonstrated a selective hydrogenation process to directly convert CO2 to light olefins via a bifunctional catalyst composed of a methanol synthesis (In2O3/ZrO2) catalyst and a methanol-to-olefins (SAPO-34) catalyst. Under typical reaction conditions (e.g., 15 bar, 400 °C, and a space velocity of 12 L gcat-1 h-1), light olefins (ethylene and propylene) with a selectivity of 80-90% in hydrocarbons can be obtained with a CO2 conversion of ∼20%. To the best of our knowledge, this is the highest selectivity reported to date, which significantly surpasses the value obtained over conventional iron or cobalt CO2 Fischer-Tropsch synthesis catalysts (typically less than 50%). Moreover, our designed bifunctional catalyst shows good catalytic stability and can run for 50 h continuously without obvious activity decay. Our study provides an important contribution for CO2 conversion to value-added chems.
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    17. 17
      Liu, X.; Wang, M.; Zhou, C.; Zhou, W.; Cheng, K.; Kang, J.; Zhang, Q.; Deng, W.; Wang, Y. Selective Transformation of Carbon Dioxide into Lower Olefins with a Bifunctional Catalyst Composed of ZnGa2O4 and SAPO-34. Chem. Commun. 2018, 54, 140– 143,  DOI: 10.1039/C7CC08642C
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      17
      Selective transformation of carbon dioxide into lower olefins with a bifunctional catalyst composed of ZnGa2O4 and SAPO-34
      Liu, Xiaoliang; Wang, Mengheng; Zhou, Cheng; Zhou, Wei; Cheng, Kang; Kang, Jincan; Zhang, Qinghong; Deng, Weiping; Wang, Ye
      Chemical Communications (Cambridge, United Kingdom) (2018), 54 (2), 140-143CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      A bifunctional catalyst composed of ZnGa2O4 with a spinel structure and mol. sieve SAPO-34 catalyzes the direct conversion of CO2 to C2-C4 olefins with a selectivity of 86% and a CO2 conversion of 13% at 370°. The O vacancies on ZnGa2O4 surfaces are responsible for CO2 activation, forming a methanol intermediate, which is then converted into C2-C4 olefins in SAPO-34.
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    18. 18
      Li, Z.; Wang, J.; Qu, Y.; Liu, H.; Tang, C.; Miao, S.; Feng, Z.; An, H.; Li, C. Highly Selective Conversion of Carbon Dioxide to Lower Olefins. ACS Catal. 2017, 7, 8544– 8548,  DOI: 10.1021/acscatal.7b03251
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      18
      Highly Selective Conversion of Carbon Dioxide to Lower Olefins
      Li, Zelong; Wang, Jijie; Qu, Yuanzhi; Liu, Hailong; Tang, Chizhou; Miao, Shu; Feng, Zhaochi; An, Hongyu; Li, Can
      ACS Catalysis (2017), 7 (12), 8544-8548CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      Conversion of CO2 to value-added chems. has been a long-standing objective, and direct hydrogenation of CO2 to lower olefins is highly desirable but still challenging. Herein, we report a selective conversion of CO2 to lower olefins through CO2 hydrogenation over a ZnZrO/SAPO tandem catalyst fabricated with a ZnO-ZrO2 solid soln. and a Zn-modified SAPO-34 zeolite, which can achieve a selectivity for lower olefins as high as 80-90% among hydrocarbon products. This is realized on the basis of the dual functions of the tandem catalyst: hydrogenation of CO2 on the ZnO-ZrO2 solid soln. and lower olefins prodn. on the SAPO zeolite. The thermodn. and kinetic coupling between the tandem reactions enable the highly efficient conversion of CO2 to lower olefins. Furthermore, this catalyst is stable toward thermal and sulfur treatments, showing potential industrial application.
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    19. 19
      Dang, S.; Gao, P.; Liu, Z.; Chen, X.; Yang, C.; Wang, H.; Zhong, L.; Li, S.; Sun, Y. Role of Zirconium in Direct CO2 Hydrogenation to Lower Olefins on Oxide/Zeolite Bifunctional Catalysts. J. Catal. 2018, 364, 382– 393,  DOI: 10.1016/j.jcat.2018.06.010
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      19
      Role of zirconium in direct CO2 hydrogenation to lower olefins on oxide/zeolite bifunctional catalysts
      Dang, Shanshan; Gao, Peng; Liu, Ziyu; Chen, Xinqing; Yang, Chengguang; Wang, Hui; Zhong, Liangshu; Li, Shenggang; Sun, Yuhan
      Journal of Catalysis (2018), 364 (), 382-393CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      Direct prodn. of lower olefins (C=2-C=4: ethylene, propylene and butylene), basic carbon-based building blocks, from carbon dioxide (CO2) hydrogenation is highly attractive, although the selectivity towards olefins has been too low. Here we present a series of bifunctional catalysts contained indium-zirconium composite oxides with different In:Zr at. ratios and SAPO-34 zeolite, which can achieve a selectivity for C=2-C=4 as high as 65-80% and that for C2-C4 of 96% with only about 2.5% methane among the hydrocarbon products at CO2 conversion of 15-27%. The selectivity of CO via the reverse water gas shift reaction is lower than 70%. The product distribution is completely different from that obtained via CO2-based Fischer-Tropsch synthesis and deviates greatly from the classical Anderson-Schulz-Flory distribution. The zirconium component plays a crit. role in detg. the physicochem. properties and catalytic performance of bifunctional catalysts. Catalyst characterization and d. functional theory calcns. demonstrate that the incorporation of a certain amt. of zirconium can create more oxygen vacancy sites, stabilize the intermediates in CO2 hydrogenation and prevent the sintering of the active nanoparticles, thus leading to significantly enhanced catalytic activity, selectivity of hydrocarbons and stability for direct CO2 hydrogenation to lower olefins at the relatively high reaction temp. of 380 °C.
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    20. 20
      Ni, Y.; Chen, Z.; Fu, Y.; Liu, Y.; Zhu, W.; Liu, Z. Selective Conversion of CO2 and H2 into Aromatics. Nat. Commun. 2018, 9, 3457,  DOI: 10.1038/s41467-018-05880-4
      Google Scholar
      20
      Selective conversion of CO2 and H2 into aromatics
      Ni Youming; Chen Zhiyang; Fu Yi; Liu Yong; Zhu Wenliang; Liu Zhongmin; Ni Youming; Chen Zhiyang; Fu Yi; Liu Yong; Zhu Wenliang; Liu Zhongmin; Chen Zhiyang; Fu Yi
      Nature communications (2018), 9 (1), 3457 ISSN:.
      Transformation of greenhouse gas CO2 and renewable H2 into fuels and commodity chemicals is recognized as a promising route to store fluctuating renewable energy. Although several C1 chemicals, olefins, and gasoline have been successfully synthesized by CO2 hydrogenation, selective conversion of CO2 and H2 into aromatics is still challenging due to the high unsaturation degree and complex structures of aromatics. Here we report a composite catalyst of ZnAlOx and H-ZSM-5 which yields high aromatics selectivity (73.9%) with extremely low CH4 selectivity (0.4%) among the carbon products without CO. Methanol and dimethyl ether, which are synthesized by hydrogenation of formate species formed on ZnAlOx surface, are transmitted to H-ZSM-5 and subsequently converted into olefins and finally aromatics. Furthermore, 58.1% p-xylene in xylenes is achieved over the composite catalyst containing Si-H-ZSM-5. ZnAlOx&H-ZSM-5 suggests a promising application in manufacturing aromatics from CO2 and H2.
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    21. 21
      Ramirez, A.; Ould-Chikh, S.; Gevers, L.; Dutta Chowdhury, A.; Abou-hamad, E.; Aguilar-Tapia, A.; Hazemann, J.; Wehbe, N.; Al Abdulghani, A. J.; Kozlov, S. M.; Cavallo, L.; Gascon, J. Tandem Conversion of CO2 to Valuable Hydrocarbons in Highly Concentrated Potassium Iron Catalysts. ChemCatChem 2019,  DOI: 10.1002/cctc.201900762
      Google Scholar
      There is no corresponding record for this reference.
    22. 22
      Ono, Y. Transformation of Lower Alkanes into Aromatic Hydrocarbons over ZSM-5 Zeolites. Catal. Rev.: Sci. Eng. 1992, 34, 179– 226,  DOI: 10.1080/01614949208020306
      Google Scholar
      22
      Transformation of lower alkanes into aromatic hydrocarbons over ZSM-5 zeolites
      Ono, Yoshio
      Catalysis Reviews - Science and Engineering (1992), 34 (3), 179-226CODEN: CRSEC9; ISSN:0161-4940.
      A review, with 76 refs., of the aromatization of C2-6-alkanes on ZSM-5 zeolites contg. Ga or Zn. Emphasis is placed on the reaction mechanism, the role of the metal cations, and the activation of the starting alkanes.
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    23. 23
      Jiao, F.; Pan, X.; Gong, K.; Chen, Y.; Li, G.; Bao, X. Shape-Selective Zeolites Promote Ethylene Formation from Syngas via a Ketene Intermediate. Angew. Chem., Int. Ed. 2018, 57, 4692,  DOI: 10.1002/anie.201801397
      Google Scholar
      23
      Shape-Selective Zeolites Promote Ethylene Formation from Syngas via a Ketene Intermediate
      Jiao, Feng; Pan, Xiulian; Gong, Ke; Chen, Yuxiang; Li, Gen; Bao, Xinhe
      Angewandte Chemie, International Edition (2018), 57 (17), 4692-4696CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Syngas conversion by Fischer-Tropsch synthesis (FTS) is characterized by a wide distribution of hydrocarbon products ranging from one to a few carbon atoms. Reported here is that the product selectivity is effectively steered toward ethylene by employing the oxide-zeolite (OX-ZEO) catalyst concept with ZnCrOx-mordenite (MOR). The selectivity of ethylene alone reaches as high as 73 % among other hydrocarbons at a 26 % CO conversion. This selectivity is significantly higher than those obtained in any other direct syngas conversion or the multistep process methanol-to-olefin conversion. This highly selective pathway is realized over the catalytic sites within the 8-membered ring (8MR) side pockets of MOR via a ketene intermediate rather than methanol in the 8MR or 12MR channels. This study provides substantive evidence for a new type of syngas chem. with ketene as the key reaction intermediate and enables extraordinary ethylene selectivity within the OX-ZEO catalyst framework.
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    24. 24
      Jiao, F.; Li, J.; Pan, X.; Xiao, J.; Li, H.; Ma, H.; Wei, M.; Pan, Y.; Zhou, Z.; Li, M.; Miao, S.; Li, J.; Zhu, Y.; Xiao, D.; He, T.; Yang, J.; Qi, F.; Fu, Q.; Bao, X. Selective conversion of syngas to light olefins. Science 2016, 351, 1065– 1068,  DOI: 10.1126/science.aaf1835
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      24
      Selective conversion of syngas to light olefins
      Jiao, Feng; Li, Jinjing; Pan, Xiulian; Xiao, Jianping; Li, Haobo; Ma, Hao; Wei, Mingming; Pan, Yang; Zhou, Zhongyue; Li, Mingrun; Miao, Shu; Li, Jian; Zhu, Yifeng; Xiao, Dong; He, Ting; Yang, Junhao; Qi, Fei; Fu, Qiang; Bao, Xinhe
      Science (Washington, DC, United States) (2016), 351 (6277), 1065-1068CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
      Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C2=-C4=) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theor. limit of only 58% for C2-C4 hydrocarbons. We present a process that reaches C2=-C4= selectivity as high as 80% and C2-C4 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrOx) activates CO and H2, and C-C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is obsd. within 110 h. Furthermore, this composite catalyst and the process may allow use of coal- and biomass-derived syngas with a low H2/CO ratio.
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    25. 25
      Van Speybroeck, V.; De Wispelaere, K.; Van der Mynsbrugge, J.; Vandichel, M.; Hemelsoet, K.; Waroquier, M. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev. 2014, 43, 7326– 7357,  DOI: 10.1039/C4CS00146J
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      25
      First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study
      Van Speybroeck, Veronique; De Wispelaere, Kristof; Van der Mynsbrugge, Jeroen; Vandichel, Matthias; Hemelsoet, Karen; Waroquier, Michel
      Chemical Society Reviews (2014), 43 (21), 7326-7357CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      To optimally design next generation catalysts a thorough understanding of the chem. phenomena at the mol. scale is a prerequisite. Apart from qual. knowledge on the reaction mechanism, it is also essential to be able to predict accurate rate consts. Mol. modeling has become a ubiquitous tool within the field of heterogeneous catalysis. Herein, we review current computational procedures to det. chem. kinetics from first principles, thus by using no exptl. input and by modeling the catalyst and reacting species at the mol. level. Therefore, we use the methanol-to-olefin (MTO) process as a case study to illustrate the various theor. concepts. This process is a showcase example where rational design of the catalyst was for a long time performed on the basis of trial and error, due to insufficient knowledge of the mechanism. For theoreticians the MTO process is particularly challenging as the catalyst has an inherent supramol. nature, for which not only the Bronsted acidic site is important but also org. species, trapped in the zeolite pores, must be essentially present during active catalyst operation. All these aspects give rise to specific challenges for theor. modeling. It is shown that present computational techniques have matured to a level where accurate enthalpy barriers and rate consts. can be predicted for reactions occurring at a single active site. The comparison with exptl. data such as apparent kinetic data for well-defined elementary reactions has become feasible as current computational techniques also allow predicting adsorption enthalpies with reasonable accuracy. Real catalysts are truly heterogeneous in a space- and time-like manner. Future theory developments should focus on extending our view towards phenomena occurring at longer length and time scales and integrating information from various scales towards a unified understanding of the catalyst. Within this respect mol. dynamics methods complemented with addnl. techniques to simulate rare events are now gradually making their entrance within zeolite catalysis. Recent applications have already given a flavor of the benefit of such techniques to simulate chem. reactions in complex mol. environments.
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    26. 26
      International Zeolite Association Home Page, http:www.iza-online.org (accessed May 25, 2019).
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      There is no corresponding record for this reference.
    27. 27
      Van Speybroeck, V.; Hemelsoet, K.; Joos, L.; Waroquier, M.; Bell, R. G.; Catlow, C. R. A. Advances in theory their application within the field of zeolite chemistry. Chem. Soc. Rev. 2015, 44, 7044– 7111,  DOI: 10.1039/C5CS00029G
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      27
      Advances in theory and their application within the field of zeolite chemistry
      Van Speybroeck, Veronique; Hemelsoet, Karen; Joos, Lennart; Waroquier, Michel; Bell, Robert G.; Catlow, C. Richard A.
      Chemical Society Reviews (2015), 44 (20), 7044-7111CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      A review. Zeolites are versatile and fascinating materials which are vital for a wide range of industries, due to their unique structural and chem. properties, which are the basis of applications in gas sepn., ion exchange and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functionalities to obtain the best material for a given application. Over the last decades, theor. modeling has matured to a level that model guided design has become within reach. Major hurdles have been overcome to reach this point and almost all contemporary methods in computational materials chem. are actively used in the field of modeling zeolite chem. and applications. Integration of complementary modeling approaches is necessary to obtain reliable predictions and rationalizations from theory. A close synergy between experimentalists and theoreticians has led to a deep understanding of the complexity of the system at hand, but also allowed the identification of shortcomings in current theor. approaches. Inspired by the importance of zeolite characterization which can now be performed at the single atom and single mol. level from expt., computational spectroscopy has grown in importance in the last decade. In this review most of the currently available modeling tools are introduced and illustrated on the most challenging problems in zeolite science. Directions for future model developments will be given.
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    28. 28
      Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 47, 558– 561,  DOI: 10.1103/PhysRevB.47.558
      Google Scholar
      28
      Ab initio molecular dynamics of liquid metals
      Kresse, G.; Hafner, J.
      Physical Review B: Condensed Matter and Materials Physics (1993), 47 (1), 558-61CODEN: PRBMDO; ISSN:0163-1829.
      The authors present ab initio quantum-mech. mol.-dynamics calcns. based on the calcn. of the electronic ground state and of the Hellmann-Feynman forces in the local-d. approxn. at each mol.-dynamics step. This is possible using conjugate-gradient techniques for energy minimization, and predicting the wave functions for new ionic positions using sub-space alignment. This approach avoids the instabilities inherent in quantum-mech. mol.-dynamics calcns. for metals based on the use of a factitious Newtonian dynamics for the electronic degrees of freedom. This method gives perfect control of the adiabaticity and allows one to perform simulations over several picoseconds.
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    29. 29
      Kresse, G.; Hafner, J. Ab initio molecular-dynamics simulation of the liquid-metal amorphous-semiconductor transition in germanium. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 49, 14251– 14269,  DOI: 10.1103/PhysRevB.49.14251
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      29
      Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium
      Kresse, G.; Hafner, J.
      Physical Review B: Condensed Matter and Materials Physics (1994), 49 (20), 14251-69CODEN: PRBMDO; ISSN:0163-1829.
      The authors present ab initio quantum-mech. mol.-dynamics simulations of the liq.-metal-amorphous-semiconductor transition in Ge. The simulations are based on (a) finite-temp. d.-functional theory of the 1-electron states, (b) exact energy minimization and hence calcn. of the exact Hellmann-Feynman forces after each mol.-dynamics step using preconditioned conjugate-gradient techniques, (c) accurate nonlocal pseudopotentials, and (d) Nose' dynamics for generating a canonical ensemble. This method gives perfect control of the adiabaticity of the electron-ion ensemble and allows the authors to perform simulations over >30 ps. The computer-generated ensemble describes the structural, dynamic, and electronic properties of liq. and amorphous Ge in very good agreement with expt.. The simulation allows the authors to study in detail the changes in the structure-property relation through the metal-semiconductor transition. The authors report a detailed anal. of the local structural properties and their changes induced by an annealing process. The geometrical, bounding, and spectral properties of defects in the disordered tetrahedral network are studied and compared with expt.
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    30. 30
      Kresse, G.; Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15– 50,  DOI: 10.1016/0927-0256(96)00008-0
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      30
      Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
      Kresse, G.; Furthmuller, J.
      Computational Materials Science (1996), 6 (1), 15-50CODEN: CMMSEM; ISSN:0927-0256. (Elsevier)
      The authors present a detailed description and comparison of algorithms for performing ab-initio quantum-mech. calcns. using pseudopotentials and a plane-wave basis set. The authors will discuss: (a) partial occupancies within the framework of the linear tetrahedron method and the finite temp. d.-functional theory, (b) iterative methods for the diagonalization of the Kohn-Sham Hamiltonian and a discussion of an efficient iterative method based on the ideas of Pulay's residual minimization, which is close to an order N2atoms scaling even for relatively large systems, (c) efficient Broyden-like and Pulay-like mixing methods for the charge d. including a new special preconditioning optimized for a plane-wave basis set, (d) conjugate gradient methods for minimizing the electronic free energy with respect to all degrees of freedom simultaneously. The authors have implemented these algorithms within a powerful package called VAMP (Vienna ab-initio mol.-dynamics package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semi-conducting surfaces, phonons in simple metals, transition metals and semiconductors) and turned out to be very reliable.
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    31. 31
      Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 11169– 11186,  DOI: 10.1103/PhysRevB.54.11169
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      31
      Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
      Kresse, G.; Furthmueller, J.
      Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
      The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
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    32. 32
      Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865– 3868,  DOI: 10.1103/PhysRevLett.77.3865
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      32
      Generalized gradient approximation made simple
      Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
      Physical Review Letters (1996), 77 (18), 3865-3868CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
      Generalized gradient approxns. (GGA's) for the exchange-correlation energy improve upon the local spin d. (LSD) description of atoms, mols., and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental consts. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential.
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    33. 33
      Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 2010, 132, 154104,  DOI: 10.1063/1.3382344
      Google Scholar
      33
      A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
      Grimme, Stefan; Antony, Jens; Ehrlich, Stephan; Krieg, Helge
      Journal of Chemical Physics (2010), 132 (15), 154104/1-154104/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      The method of dispersion correction as an add-on to std. Kohn-Sham d. functional theory (DFT-D) has been refined regarding higher accuracy, broader range of applicability, and less empiricism. The main new ingredients are atom-pairwise specific dispersion coeffs. and cutoff radii that are both computed from first principles. The coeffs. for new eighth-order dispersion terms are computed using established recursion relations. System (geometry) dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination nos. (CN). They are used to interpolate between dispersion coeffs. of atoms in different chem. environments. The method only requires adjustment of two global parameters for each d. functional, is asymptotically exact for a gas of weakly interacting neutral atoms, and easily allows the computation of at. forces. Three-body nonadditivity terms are considered. The method has been assessed on std. benchmark sets for inter- and intramol. noncovalent interactions with a particular emphasis on a consistent description of light and heavy element systems. The mean abs. deviations for the S22 benchmark set of noncovalent interactions for 11 std. d. functionals decrease by 15%-40% compared to the previous (already accurate) DFT-D version. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C6 coeffs. also lead to a much better description of large (infinite) systems as shown for graphene sheets and the adsorption of benzene on an Ag(111) surface. For graphene it is found that the inclusion of three-body terms substantially (by about 10%) weakens the interlayer binding. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in mols. and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems. (c) 2010 American Institute of Physics.
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    34. 34
      Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775,  DOI: 10.1103/PhysRevB.59.1758
      Google Scholar
      34
      From ultrasoft pseudopotentials to the projector augmented-wave method
      Kresse, G.; Joubert, D.
      Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
      The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
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    35. 35
      Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17953– 17979,  DOI: 10.1103/PhysRevB.50.17953
      Google Scholar
      35
      Projector augmented-wave method
      Blochl
      Physical review. B, Condensed matter (1994), 50 (24), 17953-17979 ISSN:0163-1829.
      There is no expanded citation for this reference.
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    36. 36
      Ghysels, A.; Van Neck, D.; Waroquier, M. Cartesian formulation of the mobile block Hessian approach to vibrational analysis in partially optimized systems. J. Chem. Phys. 2007, 127, 164108,  DOI: 10.1063/1.2789429
      Google Scholar
      36
      Cartesian formulation of the mobile block Hessian approach to vibrational analysis in partially optimized systems
      Ghysels, A.; Van Neck, D.; Waroquier, M.
      Journal of Chemical Physics (2007), 127 (16), 164108/1-164108/9CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      Partial optimization is a useful technique to reduce the computational load in simulations of extended systems. In such nonequil. structures, the accurate calcn. of localized vibrational modes can be troublesome, since the std. normal mode anal. becomes inappropriate. In a previous paper, the mobile block Hessian (MBH) approach was presented to deal with the vibrational anal. in partially optimized systems. In the MBH model, the nonoptimized regions of the system are represented by one or several blocks, which can move as rigid bodies with respect to the atoms of the optimized region. In this way unphys. imaginary frequencies are avoided and the translational/rotational invariance of the potential energy surface is fully respected. In this paper we focus on issues concerning the practical numerical implementation of the MBH model. The MBH normal mode equations are worked out for several coordinate choices. The introduction of a consistent group-theor. notation facilitates the treatment of both the case of a single block and the case of multiple blocks. Special attention is paid to the formulation in terms of Cartesian variables, in order to provide a link with the std. output of common mol. modeling programs.
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    37. 37
      Reetz, M. T.; Meiswinkel, A.; Mehler, G.; Angermund, K.; Graf, M.; Thiel, W.; Mynott, R.; Blackmond, D. G. Why Are BINOL-Based Monophosphites Such Efficient Ligands in Rh-Catalyzed Asymmetric Olefin Hydrogenation?. J. Am. Chem. Soc. 2005, 127, 10305– 10313,  DOI: 10.1021/ja052025+
      Google Scholar
      37
      Why Are BINOL-Based Monophosphites Such Efficient Ligands in Rh-Catalyzed Asymmetric Olefin Hydrogenation?
      Reetz, Manfred T.; Meiswinkel, Andreas; Mehler, Gerlinde; Angermund, Klaus; Graf, Martin; Thiel, Walter; Mynott, Richard; Blackmond, Donna G.
      Journal of the American Chemical Society (2005), 127 (29), 10305-10313CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Whereas recent synthetic studies concerning Rh-catalyzed olefin hydrogenation based on BINOL-derived monodentate phosphites have resulted in an efficient and economically attractive preparative method, very little is known concerning the source of the unexpectedly high levels of enantioselectivity (ee often 90-99%). The present mechanistic study, which includes the NMR characterization of the precatalysts, kinetic measurements with focus on nonlinear effects, and DFT calcns., constitutes a first step in understanding this hydrogenation system. The two most important features which have emerged from these efforts are the following: (1) two monodentate P-ligands are attached to rhodium, and (2) the lock-and-key mechanism holds, in which the thermodn. of Rh/olefin complexation with formation of the major and minor diastereomeric intermediates dictates the stereochem. outcome. The major diastereomer leads to the favored enantiomeric product, which is opposite to the state of affairs in classical Rh-catalyzed olefin hydrogenation based on chiral chelating diphosphines (anti lock-and-key mechanism as proposed by Halpern).
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    38. 38
      Donoghue, P. J.; Helquist, P.; Norrby, P. O.; Wiest, O. Development of a Q2MM Force Field for the Asymmetric Rhodium Catalyzed Hydrogenation of Enamides. J. Chem. Theory Comput. 2008, 4, 1313– 1323,  DOI: 10.1021/ct800132a
      Google Scholar
      38
      Development of a Q2MM Force Field for the Asymmetric Rhodium Catalyzed Hydrogenation of Enamides
      Donoghue, Patrick J.; Helquist, Paul; Norrby, Per-Ola; Wiest, Olaf
      Journal of Chemical Theory and Computation (2008), 4 (8), 1313-1323CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)
      The rhodium catalyzed asym. hydrogenation of enamides to generate amino acid products and derivs. is a widely used method to generate unnatural amino acids. The choice of a chiral ligand is of utmost importance in this reaction and is often based on high throughput screening or simply trial and error. A virtual screening method can greatly increase the speed of the ligand screening process by calcg. expected enantiomeric excesses from relative energies of diastereomeric transition states. Utilizing the Q2MM method, new mol. mechanics parameters are derived to model the hydride transfer transition state in the reaction. The new parameters were based off of structures calcd. at the B3LYP/LACVP** level of theory and added to the MM3* force field. The new parameters were validated against a test set of exptl. data utilizing a wide range of bis-phosphine ligands. The computational model agreed with exptl. data well overall, with an unsigned mean error of 0.6 kcal/mol against a set of 18 data points from expt. The major errors in the computational model were due either to large energetic errors at high e.e., still resulting in qual. agreement, or cases where large steric interactions prevent the reaction from proceeding as expected.
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    39. 39
      Ghysels, A.; Verstraelen, T.; Hemelsoet, K.; Waroquier, M.; Van Speybroeck, V. TAMkin: A Versatile Package for Vibrational Analysis and Chemical Kinetics. J. Chem. Inf. Model. 2010, 50, 1736– 1750,  DOI: 10.1021/ci100099g
      Google Scholar
      39
      TAMkin: A Versatile Package for Vibrational Analysis and Chemical Kinetics
      Ghysels, An; Verstraelen, Toon; Hemelsoet, Karen; Waroquier, Michel; Van Speybroeck, Veronique
      Journal of Chemical Information and Modeling (2010), 50 (9), 1736-1750CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)
      TAMkin is a program for the calcn. and anal. of normal modes, thermochem. properties and chem. reaction rates. At present, the output from the frequently applied software programs ADF, CHARMM, CPMD, CP2K, Gaussian, Q-Chem, and VASP can be analyzed. The normal-mode anal. can be performed using a broad variety of advanced models, including the std. full Hessian, the Mobile Block Hessian, the Partial Hessian Vibrational approach, the Vibrational Subsystem Anal. with or without mass matrix correction, the Elastic Network Model, and other combinations. TAMkin is readily extensible because of its modular structure. Chem. kinetics of unimol. and bimol. reactions can be analyzed in a straightforward way using conventional transition state theory, including tunneling corrections and internal rotor refinements. A sensitivity anal. can also be performed, providing important insight into the theor. error margins on the kinetic parameters. Two extensive examples demonstrate the capabilities of TAMkin: the conformational change of the biol. system adenylate kinase is studied, as well as the reaction kinetics of the addn. of ethene to the Et radical. The important feature of batch processing large amts. of data is highlighted by performing an extended level of theory study, which TAMkin can automate significantly.
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    40. 40
      Van de Vondele, J.; Krack, M.; Mohamed, F.; Parrinello, M.; Chassaing, T.; Hutter, J. QUICKSTEP: Fast and accurate density functional calculations using a mixed Gaussian and plane waves approach. Comput. Phys. Commun. 2005, 167, 103– 128,  DOI: 10.1016/j.cpc.2004.12.014
      Google Scholar
      40
      QUICKSTEP: fast and accurate density functional calculations using a mixed Gaussian and plane waves approach
      VandeVondele, Joost; Krack, Matthias; Mohamed, Fawzi; Parrinello, Michele; Chassaing, Thomas; Hutter, Juerg
      Computer Physics Communications (2005), 167 (2), 103-128CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)
      We present the Gaussian and plane waves (GPW) method and its implementation in which is part of the freely available program package CP2K. The GPW method allows for accurate d. functional calcns. in gas and condensed phases and can be effectively used for mol. dynamics simulations. We show how derivs. of the GPW energy functional, namely ionic forces and the Kohn-Sham matrix, can be computed in a consistent way. The computational cost of computing the total energy and the Kohn-Sham matrix is scaling linearly with the system size, even for condensed phase systems of just a few tens of atoms. The efficiency of the method allows for the use of large Gaussian basis sets for systems up to 3000 atoms, and we illustrate the accuracy of the method for various basis sets in gas and condensed phases. Agreement with basis set free calcns. for single mols. and plane wave based calcns. in the condensed phase is excellent. Wave function optimization with the orbital transformation technique leads to good parallel performance, and outperforms traditional diagonalisation methods. Energy conserving Born-Oppenheimer dynamics can be performed, and a highly efficient scheme is obtained using an extrapolation of the d. matrix. We illustrate these findings with calcns. using commodity PCs as well as supercomputers.
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    41. 41
      Yang, K.; Zheng, J.; Zhao, Y.; Truhlar, D. G. Tests of the RPBE, revPBE, τ-HCTHhyb, ωB97X-D, and MOHLYP density functional approximations and 29 others against representative databases for diverse bond energies and barrier heights in catalysis. J. Chem. Phys. 2010, 132, 164117,  DOI: 10.1063/1.3382342
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      41
      Tests of the RPBE, revPBE, τ-HCTHhyb, ωB97X-D, and MOHLYP density functional approximations and 29 others against representative databases for diverse bond energies and barrier heights in catalysis
      Yang, Ke; Zheng, Jing-Jing; Zhao, Yan; Truhlar, Donald G.
      Journal of Chemical Physics (2010), 132 (16), 164117/1-164117/10CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      Thirty four d. functional approxns. are tested against two diverse databases, one with 18 bond energies and one with 24 barriers. These two databases are chosen to include bond energies and barrier heights which are relevant to catalysis, and in particular the bond energy database includes metal-metal bonds, metal-ligand bonds, alkyl bond dissocn. energies, and atomization energies of small main group mols. Two revised versions of the Perdew-Burke-Ernzerhof (PBE) functional, namely the RPBE and revPBE functionals, widely used for catalysis, do improve the performance of PBE against the two diverse databases, but give worse results than B3LYP (which denotes the combination of Becke's 3-parameter hybrid treatment with Lee-Yang-Parr correlation functional). Our results show that the Minnesota functionals, M05, M06, and M06-L give the best performance for the two diverse databases, which suggests that they deserve more attention for applications to catalysis. We also obtain notably good performance with the τ-HCTHhyb, ωB97X-D, and MOHLYP functional (where MOHLYP denotes the combination of the OptX exchange functional as modified by Schultz, Zhao, and Truhlar with half of the LYP correlation functional). (c) 2010 American Institute of Physics.
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    42. 42
      Goedecker, S.; Teter, M.; Hutter, J. Separable dual-space Gaussian pseudopotentials. Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 1703– 1710,  DOI: 10.1103/PhysRevB.54.1703
      Google Scholar
      42
      Separable dual-space Gaussian pseudopotentials
      Goedecker, S.; Teter, M.; Hutter, J.
      Physical Review B: Condensed Matter (1996), 54 (3), 1703-1710CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)
      We present pseudopotential coeffs. for the first two rows of the Periodic Table. The pseudopotential is of an analytic form that gives optimal efficiency in numerical calculations using plane waves as a basis set. At most, even coeffs. are necessary to specify its analytic form. It is separable and has optimal decay properties in both real and Fourier space. Because of this property, the application of the nonlocal part of the pseudopotential to a wave function can be done efficiently on a grid in real space. Real space integration is much faster for large systems than ordinary multiplication in Fourier space, since it shows only quadratic scaling with respect to the size of the system. We systematically verify the high accuracy of these pseudopotentials by extensive at. and mol. test calcns.
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    43. 43
      Lippert, G.; Hutter, J.; Parrinello, M. The Gaussian and augmented-plane-wave density functional method for ab initio molecular dynamics simulations. Theor. Chem. Acc. 1999, 103, 124– 140,  DOI: 10.1007/s002140050523
      Google Scholar
      43
      The Gaussian and augmented-plane-wave density functional method for ab initio molecular dynamics simulations
      Lippert, Gerald; Hutter, Jurg; Parrinello, Michele
      Theoretical Chemistry Accounts (1999), 103 (2), 124-140CODEN: TCACFW; ISSN:1432-881X. (Springer-Verlag)
      A new algorithm for d.-functional-theory-based ab initio mol. dynamics simulations is presented. The Kohn-Sham orbitals are expanded in Gaussian-type functions and an APW-type approach is used to represent the electronic d. This extends previous work of ours where the d. was expanded only in plane waves. We describe the total d. in a smooth extended part which we represent in plane waves as in our previous work and parts localized close to the nuclei which are expanded in Gaussians. Using this representation of the charge we show how the localized and extended part can be treated sep., achieving a computational cost for the calcn. of the Kohn-Sham matrix that scales with the system size N as O(N log N). Furthermore, we are able to reduce drastically the size of the plane-wave basis. In addn., we introduce a multiple-cutoff method that improves considerably the performance of this approach. Finally, we demonstrate with a series of numerical examples the accuracy and efficiency of the new algorithm, both for electronic structure calcns. and for ab initio mol. dynamics simulations.
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    44. 44
      Lippert, G.; Hutter, J.; Parrinello, M. A hybrid Gaussian and plane wave density functional scheme. Mol. Phys. 1997, 92, 477– 488,  DOI: 10.1080/00268979709482119
      Google Scholar
      44
      A hybrid Gaussian and plane wave density functional scheme
      Lippert, Gerald; Hutter, Juerg; Parrinello, Michele
      Molecular Physics (1997), 92 (3), 477-487CODEN: MOPHAM; ISSN:0026-8976. (Taylor & Francis)
      A d.-functional theory-based algorithm for periodic and nonperiodic ab initio calcns. is presented. This scheme uses pseudopotentials in order to integrate out the core electrons from the problem. The valence pseudo wave functions are expanded in Gaussian-type orbitals and the d. is represented in a plane wave auxiliary basis. The Gaussian basis functions make it possible to use the efficient anal. integration schemes and screening algorithms of quantum chem. Novel recursion relations are developed for the calcn. of the matrix elements of the d.-dependent Kohn-Sham self-consistent potential. At the same time the use of a plane wave basis for the electron d. permits efficient calcn. of the Hartree energy using fast Fourier transforms, thus circumventing one of the major bottlenecks of std. Gaussian based calcns. Furthermore, this algorithm avoids the fitting procedures that go along with intermediate basis sets for the charge d. The performance and accuracy of this new scheme are discussed and selected examples are given.
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    45. 45
      Nosé, S. A molecular dynamics method for simulations in the canonical ensemble. Mol. Phys. 1984, 52, 255– 268,  DOI: 10.1080/00268978400101201
      Google Scholar
      45
      A molecular dynamics method for simulations in the canonical ensemble
      Nose, Shuichi
      Molecular Physics (1984), 52 (2), 255-68CODEN: MOPHAM; ISSN:0026-8976.
      A mol. dynamics simulation method is proposed which can generate configurations belonging to the canonical (T, V, N) ensemble or the const. temp. const. pressure (T, P, N) ensemble. The phys. system of interest consists of N particles (f degrees of freedom), to which an external, macroscopic variable and its conjugate momentum are added. This device allows the total energy of the phys. system to fluctuate. The equil. distribution of the energy coincides with the canonical distribution both in momentum and in coordinate space. The method is tested for an at. fluid (Ar) and works well.
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    46. 46
      Martyna, G. J.; Klein, M. L.; Tuckerman, M. Nosé-Hoover chains: The canonical ensemble via continuous dynamics. J. Chem. Phys. 1992, 97, 2635– 2643,  DOI: 10.1063/1.463940
      Google Scholar
      There is no corresponding record for this reference.
    47. 47
      Martyna, G. J.; Tobias, D. J.; Klein, M. L. Constant pressure molecular dynamics algorithms. J. Chem. Phys. 1994, 101, 4177– 4189,  DOI: 10.1063/1.467468
      Google Scholar
      47
      Constant pressure molecular dynamics algorithms
      Martyna, Glenn J.; Tobias, Douglas J.; Klein, Michael L.
      Journal of Chemical Physics (1994), 101 (5), 4177-89CODEN: JCPSA6; ISSN:0021-9606.
      Modularly invariant equations of motion are derived that generate the isothermal-isobaric ensemble as their phase space avs. Isotropic vol. fluctuations and fully flexible simulation cells as well as a hybrid scheme that naturally combines the two motions are considered. The resulting methods are tested on two problems, a particle in a one-dimensional periodic potential and a spherical model of C60 in the solid/fluid phase.
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    48. 48
      Tribello, G. A.; Bonomi, M.; Branduardi, D.; Camilloni, C.; Bussi, G. PLUMED 2: New feathers for an old bird. Comput. Phys. Commun. 2014, 185, 604– 613,  DOI: 10.1016/j.cpc.2013.09.018
      Google Scholar
      48
      PLUMED 2: New feathers for an old bird
      Tribello, Gareth A.; Bonomi, Massimiliano; Branduardi, Davide; Camilloni, Carlo; Bussi, Giovanni
      Computer Physics Communications (2014), 185 (2), 604-613CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier B.V.)
      Enhancing sampling and analyzing simulations are central issues in mol. simulation. Recently, we introduced PLUMED, an open-source plug-in that provides some of the most popular mol. dynamics (MD) codes with implementations of a variety of different enhanced sampling algorithms and collective variables (CVs). The rapid changes in this field, in particular new directions in enhanced sampling and dimensionality redn. together with new hardware, require a code that is more flexible and more efficient. We therefore present PLUMED 2 here-a complete rewrite of the code in an object-oriented programming language (C++). This new version introduces greater flexibility and greater modularity, which both extends its core capabilities and makes it far easier to add new methods and CVs. It also has a simpler interface with the MD engines and provides a single software library contg. both tools and core facilities. Ultimately, the new code better serves the ever-growing community of users and contributors in coping with the new challenges arising in the field.
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    49. 49
      Cnudde, P.; De Wispelaere, K.; Vanduyfhuys, L.; Demuynck, R.; Waroquier, M.; Van Speybroeck, V.; Van der Mynsbrugge, J. How Chain Length and Branching Influence the Alkene Cracking Reactivity on H-ZSM-5. ACS Catal. 2018, 8, 9579– 9595,  DOI: 10.1021/acscatal.8b01779
      Google Scholar
      49
      How Chain Length and Branching Influence the Alkene Cracking Reactivity on H-ZSM-5
      Cnudde, Pieter; De Wispelaere, Kristof; Vanduyfhuys, Louis; Demuynck, Ruben; Van der Mynsbrugge, Jeroen; Waroquier, Michel; Van Speybroeck, Veronique
      ACS Catalysis (2018), 8 (10), 9579-9595CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      Catalytic alkene cracking on H-ZSM-5 involves a complex reaction network with many possible reaction routes and often elusive intermediates. Herein, advanced mol. dynamics simulations at 773 K, a typical cracking temp., are performed to clarify the nature of the intermediates and to elucidate dominant cracking pathways at operating conditions. A series of C4-C8 alkene intermediates are investigated to evaluate the influence of chain length and degree of branching on their stability. Our simulations reveal that linear, secondary carbenium ions are relatively unstable, although their lifetime increases with carbon no. Tertiary carbenium ions, on the other hand, are shown to be very stable, irresp. of the chain length. Highly branched carbenium ions, though, tend to rapidly rearrange into more stable cationic species, either via cracking or isomerization reactions. Dominant cracking pathways were detd. by combining these insights on carbenium ion stability with intrinsic free energy barriers for various octene β-scission reactions, detd. via umbrella sampling simulations at operating temp. (773 K). Cracking modes A (3° → 3°) and B2 (3° → 2°) are expected to be dominant at operating conditions, whereas modes B1 (2° → 3°), C (2° → 2°), D2 (2° → 1°), and E2 (3° → 1°) are expected to be less important. All β-scission modes in which a transition state with primary carbocation character is involved have high intrinsic free energy barriers. Reactions starting from secondary carbenium ions will contribute less as these intermediates are short living at the high cracking temp. Our results show the importance of simulations at operating conditions to properly evaluate the carbenium ion stability for β-scission reactions and to assess the mobility of all species in the pores of the zeolite.
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    50. 50
      Kästner, J. Umbrella sampling. WIREs Comput. Mol. Sci. 2011, 1, 932– 942,  DOI: 10.1002/wcms.66
      Google Scholar
      There is no corresponding record for this reference.
    51. 51
      Kumar, S.; Rosenberg, J. M.; Bouzida, D.; Swendsen, R. H.; Kollman, P. A. The weighted histogram analysis method for free-energy calculations on biomolecules. I. The method. J. Comput. Chem. 1992, 13, 1011– 1021,  DOI: 10.1002/jcc.540130812
      Google Scholar
      51
      The weighted histogram analysis method for free-energy calculations on biomolecules. I. The method
      Kumar, Shankar; Bouzida, Djamal; Swendsen, Robert H.; Kollman, Peter A.; Rosenberg, John M.
      Journal of Computational Chemistry (1992), 13 (8), 1011-21CODEN: JCCHDD; ISSN:0192-8651.
      The Weighted Histogram Anal. Method (WHAM), an extension of Ferrenberg and Swendsen's Multiple Histogram Technique, has been applied for the first time on complex biomol. Hamiltonians. The method is presented here as an extension of the Umbrella Sampling method for free-energy and Potential of Mean Force calcns. This algorithm possesses the following advantages over methods that are currently employed: (1) it provides a built-in est. of sampling errors thereby yielding objective ests. of the optimal location and length of addnl. simulations needed to achieve a desired level of precision; (2) it yields the "best" value of free energies by taking into account all the simulations so as to minimize the statistical errors; (3) in addn. to optimizing the links between simulations, it also allows multiple overlaps of probability distributions for obtaining better ests. of the free-energy differences. By recasting the Ferrenberg-Swendsen Multiple Histogram equations in a form suitable for mol. mechanics type Hamiltonians, we have demonstrated the feasibility and robustness of this method by applying it to a test problem of the generation of the Potential of Mean Force profile of the pseudorotation phase angle of the sugar ring in deoxyadenosine.
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    52. 52
      Souaille, M.; Roux, B. Extension to the weighted histogram analysis method: combining umbrella sampling with free energy calculations. Comput. Phys. Commun. 2001, 135, 40– 57,  DOI: 10.1016/S0010-4655(00)00215-0
      Google Scholar
      52
      Extension to the weighted histogram analysis method: combining umbrella sampling with free energy calculations
      Souaille, M.; Roux, B.
      Computer Physics Communications (2001), 135 (1), 40-57CODEN: CPHCBZ; ISSN:0010-4655. (Elsevier Science B.V.)
      The Weighted Histogram Anal. Method (WHAM) of Kumar et al. (J. Comput. Chem. 13 (1992) 1011), is used to combine free energy perturbations with umbrella sampling calcns. The formulation is general and allows optimal calcn. of the free energies from a set of mol. dynamics simulations generated in the presence of arbitrary biasing umbrella sampling window potentials. The method yields the free energy assocd. with a given simulation as well as the probability distribution of the mol. system configurations by extg. the information contained in all the biased simulations (the windows) in an optimal way. The method presents some advantages compared to the std. free energy perturbation (FEP) and thermodn. integration (TI) methods, because the window potential can be used for restricting the conformational space to specific regions during free energy calcns.
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    53. 53
      Cheng, K.; Zhou, W.; Kang, J.; He, S.; Shi, S.; Zhang, Q.; Pan, Y.; Wen, W.; Wang, Y. Bifunctional Catalysts for One-Step Conversion of Syngas into Aromatics with Excellent Selectivity and Stability. Chem. 2017, 3, 334– 347,  DOI: 10.1016/j.chempr.2017.05.007
      Google Scholar
      53
      Bifunctional Catalysts for One-Step Conversion of Syngas into Aromatics with Excellent Selectivity and Stability
      Cheng, Kang; Zhou, Wei; Kang, Jincan; He, Shun; Shi, Shulin; Zhang, Qinghong; Pan, Yang; Wen, Wu; Wang, Ye
      Chem (2017), 3 (2), 334-347CODEN: CHEMVE; ISSN:2451-9294. (Cell Press)
      Syngas (CO/H2) is a key platform for chem. utilization of non-petroleum carbon resources. Among syngas transformation routes, the direct synthesis of aroms., which are among the most important bulk chems., is less successful because of the limited selectivity and poor catalyst stability. We report a successful design of bifunctional catalysts composed of Zn-doped ZrO2 nanoparticles dispersed on zeolite H-ZSM-5 for one-step conversion of syngas to aroms. with high selectivity and stability. Aroms. with 80% selectivity at CO conversion of 20% were achieved, and there was no catalyst deactivation in 1,000 h. Methanol and di-Me ether were formed as major intermediates on Zn-doped ZrO2, which were subsequently converted into aroms. on H-ZSM-5 via olefins. We discovered a self-promotion mechanism of CO in the selective formation of aroms. As well as being a reactant, CO facilitates the removal of hydrogen species formed on H-ZSM-5 in the dehydrogenative aromatization of olefins.
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    54. 54
      Guisnet, M.; Gnep, N. S.; Alario, F. Aromatization of short chain alkanes on zeolite catalysts. Appl. Catal., A 1992, 89, 1– 30,  DOI: 10.1016/0926-860X(92)80075-N
      Google Scholar
      54
      Aromatization of short chain alkanes on zeolite catalysts
      Guisnet, M.; Gnep, N. S.; Alario, F.
      Applied Catalysis, A: General (1992), 89 (1), 1-30CODEN: ACAGE4; ISSN:0926-860X.
      A review with 95 refs. covering principally GaHZSM 5 and Ga-substituted MFI-type zeolite catalysts.
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    55. 55
      Dutta Chowdhury, A.; Paioni, A. L.; Houben, K.; Whiting, G. T.; Baldus, M.; Weckhuysen, B. M. Bridging the Gap between the Direct and Hydrocarbon Pool Mechanisms of the Methanol-to-Hydrocarbon Process. Angew. Chem., Int. Ed. 2018, 57, 8095– 8099,  DOI: 10.1002/anie.201803279
      Google Scholar
      There is no corresponding record for this reference.
    56. 56
      Yarulina, I.; Dutta Chowdhury, A.; Meirer, F.; Weckhuysen, B. M.; Gascon, J. Recent Trends and Fundamental Insights in the Methanol-to-Olefins Process. Nat. Catal. 2018, 1, 398– 411,  DOI: 10.1038/s41929-018-0078-5
      Google Scholar
      56
      Recent trends and fundamental insights in the methanol-to-hydrocarbons process
      Yarulina, Irina; Chowdhury, Abhishek Dutta; Meirer, Florian; Weckhuysen, Bert M.; Gascon, Jorge
      Nature Catalysis (2018), 1 (6), 398-411CODEN: NCAACP; ISSN:2520-1158. (Nature Research)
      The prodn. of high-demand chem. commodities such as ethylene and propylene (methanol-to-olefins), hydrocarbons (methanol-to-hydrocarbons), gasoline (methanol-to-gasoline) and aroms. (methanol-to-aroms.) from methanol-obtainable from alternative feedstocks, such as carbon dioxide, biomass, waste or natural gas through the intermediate formation of synthesis gas-has been central to research in both academia and industry. Although discovered in the late 1970s, this catalytic technol. has only been industrially implemented over the past decade, with a no. of large com. plants already operating in Asia. However, as is the case for other technologies, industrial maturity is not synonymous with full understanding. For this reason, research is still intense and a no. of important discoveries have been reported over the last few years. In this review, we summarize the most recent advances in mechanistic understanding-including direct C-C bond formation during the induction period and the promotional effect of zeolite topol. and acidity on the alkene cycle-and correlate these insights to practical aspects in terms of catalyst design and engineering.
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    57. 57
      Dutta Chowdhury, A.; Houben, K.; Whiting, G. T.; Mokhtar, M.; Asiri, A. M.; Al-Thabaiti, S. A.; Baldus, M.; Weckhuysen, B. M.; Basahel, S. N. Initial carbon-carbon bond formation during the early stages of the methanol-to-olefin process proven by zeolite-trapped acetate and methyl acetate. Angew. Chem., Int. Ed. 2016, 55, 15840– 15845,  DOI: 10.1002/anie.201608643
      Google Scholar
      There is no corresponding record for this reference.
    58. 58
      Ristanović, Z.; Dutta Chowdhury, A.; Brogaard, R. Y.; Houben, K.; Baldus, M.; Hofkens, J.; Roeffaers, M. B. J.; Weckhuysen, B. M. Reversible and Site-Dependent Proton-Transfer in Zeolites Uncovered at the Single-Molecule Level. J. Am. Chem. Soc. 2018, 140, 14195– 14205,  DOI: 10.1021/jacs.8b08041
      Google Scholar
      58
      Reversible and Site-Dependent Proton-Transfer in Zeolites Uncovered at the Single-Molecule Level
      Ristanovic, Zoran; Chowdhury, Abhishek Dutta; Brogaard, Rasmus Y.; Houben, Klaartje; Baldus, Marc; Hofkens, Johan; Roeffaers, Maarten B. J.; Weckhuysen, Bert M.
      Journal of the American Chemical Society (2018), 140 (43), 14195-14205CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Zeolite activity and selectivity is often detd. by the underlying proton and hydrogen-transfer reaction pathways. For the first time, we use single-mol. fluorescence microscopy to directly follow the real-time behavior of individual styrene-derived carbocationic species formed within zeolite ZSM-5. We find that intermittent fluorescence and remarkable photostability of carbocationic intermediates strongly depend on the local chem. environment imposed by zeolite framework and guest solvent mols. The carbocationic stability can be addnl. altered by changing para-substituent on the styrene moiety, as suggested by DFT calcns. Thermodynamically unstable carbocations are more likely to switch between fluorescent (carbocationic) and dark (neutral) states. However, the rate consts. of this reversible change can significantly differ among individual carbocations, depending on their exact location in the zeolite framework. The lifetimes of fluorescent states and reversibility of the process can be addnl. altered by changing the interaction between dimeric carbocations and solvated Bronsted acid sites in the MFI framework. Advanced multidimensional magic angle spinning solid-state NMR spectroscopy has been employed for the accurate structural elucidation of the reaction products during the zeolite-catalyzed dimerization of styrene in order to corroborate the single-mol. fluorescence microscopy data. This complementary approach of single-mol. fluorescence microscopy, NMR, and DFT collectively indicates that the relative stability of the carbocationic and the neutral states largely depends on the substituent and the local position of the Bronsted acid site within the zeolite framework. As a consequence, new insights into the host-guest chem. between the zeolite and aroms., in terms of their surface mobility and reactivity, have been obtained.
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    59. 59
      Persson, I. Hydrated metal ions in aqueous solution: How regular are their structures?. Pure Appl. Chem. 2010, 82, 1901– 1917,  DOI: 10.1351/PAC-CON-09-10-22
      Google Scholar
      59
      Hydrated metal ions in aqueous solution: how regular are their structures?
      Persson, Ingmar
      Pure and Applied Chemistry (2010), 82 (10), 1901-1917CODEN: PACHAS; ISSN:0033-4545. (International Union of Pure and Applied Chemistry)
      A review. The hydration reaction is defined as the transfer of an ion or neutral chem. species from the gaseous phase into water, Mn+(g) → Mn+(aq). In this process, water mols. bind to metal ions through ion-dipole bonds of mainly electrostatic character. The hydration reaction is always strongly exothermic with increasing heat of hydration with increasing charge d. of the ion. The structures of the hydrated metal ions in aq. soln. display a variety of configurations depending on the size and electronic properties of the metal ion. The basic configurations of hydrated metal ions in aq. soln. are tetrahedral, octahedral, square antiprismatic, and tricapped trigonal prismatic. This paper gives an overview of the structures of hydrated metal ions in aq. soln. with special emphasis on those with a non-regular coordination figure. Metal ions without d-electrons in the valance shell form regular aqua complexes with a coordination figure, allowing a max. no. of water mols. to be clustered around the metal ion. This no. is dependent on the ratio of the metal ion radius to the at. radius of oxygen in a coordinated water mol. (1.34 Å). The lighter lanthanoid(III) ions have a regular tricapped trigonal prismatic configuration with the M-O distance to the capping water mols. somewhat longer than to the prismatic ones. However, with increasing at. no. of the lanthanoid(III) ions, an increasing distortion of the capping water mols. is obsd., resulting in a partial loss of water mols. in the capping positions for the heaviest lanthanoids. Metal ions with d4 and d9 valance shell electron configuration, as chromium(II) and copper(II), resp., have Jahn-Teller distorted aqua complexes. Metal ions with low charge and ability to form strong covalent bonds, as silver(I), mercury(II), palladium(II), and platinum(II), often display distorted coordination figures due to the second-order Jahn-Teller effect. Metal ions with d10s2 valence shell electron configuration may have a stereochem. active lone electron pair (hemi-directed complexes) or an inactive one (holo-directed). The hydrated tin(II), lead(II), and thallium(I) ions are hemi-directed in aq. soln., while the hydrated bismuth(III) ion is holo-directed. The structures of the hydrated cationic oxo-metal ions are reported as well.
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    60. 60
      Weitkamp, J. Catalytic Hydrocracking-Mechanisms and Versatility of the Process. ChemCatChem 2012, 4, 292– 306,  DOI: 10.1002/cctc.201100315
      Google Scholar
      60
      Catalytic Hydrocracking-Mechanisms and Versatility of the Process
      Weitkamp, Jens
      ChemCatChem (2012), 4 (3), 292-306CODEN: CHEMK3; ISSN:1867-3880. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Hydrocracking of satd. hydrocarbons can proceed by four distinctly different mechanisms. On bifunctional catalysts comprising hydrogenation/dehydrogenation and Broensted acid sites alkenes and carbocations occur as intermediates. The current mechanistic views of bifunctional hydrocracking of long-chain n-alkanes are discussed in detail with emphasis on the now widely accepted concept of ideal hydrocracking. Other mechanisms are hydrogenolysis and Haag-Dessau hydrocracking which proceed, resp., on monofunctional metallic and acidic catalysts. Even without a catalyst, thermal hydrocracking occurs in chain reactions via radicals. The chem. of hydrocracking naphthenes on bifunctional catalysts resembles that of alkanes. A peculiarity, however, is the pronounced reluctance of cyclic carbenium ions to undergo endocyclic β-scissions. The effect manifests itself in the so-called paring reaction, which, in turn, forms the basis for measuring the Spaciousness Index for characterizing the effective pore width of zeolitic catalysts. Hydrocracking on bifunctional catalysts is among the very important processes in modern petroleum refining. It is primarily used for converting heavy oils into diesel and jet fuel. Besides, hydrocracking is appreciated for its pronounced versatility: numerous process variants exist which help to meet specific requirements in refineries or petrochem. plants. Two recent developments are briefly discussed in this review, viz. the conversion of surplus aroms., e.g., in pyrolysis gasoline, into a synthetic feedstock for steam crackers, and quality enhancement of diesel fuel by selective ring opening of polynuclear aroms.
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    61. 61
      Kissin, Y. V. Chemical Mechanisms of Catalytic Cracking Over Solid Acidic Catalysts: Alkanes and Alkenes. Catal. Rev.: Sci. Eng. 2001, 43, 85– 146,  DOI: 10.1081/CR-100104387
      Google Scholar
      61
      Chemical mechanisms of catalytic cracking over solid acidic catalysts: alkanes and alkenes
      Kissin, Yury V.
      Catalysis Reviews - Science and Engineering (2001), 43 (1 & 2), 85-146CODEN: CRSEC9; ISSN:0161-4940. (Marcel Dekker, Inc.)
      A review with 186 refs. on the mechanisms of catalytic cracking of alkenes and alkanes over solid acidic catalysts.
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    62. 62
      Martínez-Espín, J. S.; De Wispelaere, K.; Janssens, T. V. W.; Svelle, S.; Lillerud, K. P.; Beato, P.; Van Speybroeck, V.; Olsbye, U. Hydrogen Transfer versus Methylation: On the Genesis of Aromatics Formation in the Methanol-To-Hydrocarbons Reaction over H-ZSM-5. ACS Catal. 2017, 7, 5773– 5780,  DOI: 10.1021/acscatal.7b01643
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      62
      Hydrogen Transfer versus Methylation: On the Genesis of Aromatics Formation in the Methanol-To-Hydrocarbons Reaction over H-ZSM-5
      Martinez-Espin, Juan S.; De Wispelaere, Kristof; Janssens, Ton V. W.; Svelle, Stian; Lillerud, Karl Petter; Beato, Pablo; Van Speybroeck, Veronique; Olsbye, Unni
      ACS Catalysis (2017), 7 (9), 5773-5780CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      The catalytic conversion of methanol (MeOH) and di-Me ether (DME) into fuels and chems. over zeolites (MTH process) is industrially emerging as an alternative route to conventional oil-derived processes. After 40 years of research, a detailed mechanistic understanding of the intricate reaction network is still not fully accomplished. The overall reaction is described as two competitive catalytic cycles, dominated by alkenes and arenes, which are methylated and cracked or dealkylated to form effluent products. Herein, we present the reaction of isobutene with methanol and DME as an efficient tool for measuring the relative formation rates of alkenes and arenes, and we provide detailed mechanistic insight into the hydrogen-transfer reaction. We provide exptl. and theor. evidence that manifest a strong competition of methylation and hydrogen transfer of isobutene by methanol, while methylation is substantially favored by DME. Expts. performed at higher conversion facilitate projection of the results to the product distribution obtained when using MeOH or DME as feedstock during the MTH reaction.
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    63. 63
      Buchanan, J. S.; Santiesteban, J. G.; Haag, W. O. Mechanistic Considerations in Acid-Catalyzed Cracking of Olefins. J. Catal. 1996, 158, 279– 287,  DOI: 10.1006/jcat.1996.0027
      Google Scholar
      63
      Mechanistic considerations in acid-catalyzed cracking of olefins
      Buchanan, J. S.; Santiesteban, J. G.; Haag, W. O.
      Journal of Catalysis (1996), 158 (1), 279-87CODEN: JCTLA5; ISSN:0021-9517. (Academic)
      The relative rates of cracking and resultant products distributions for cracking C5-C8 olefins over ZSM-5 at 510°C were quantified and rationalized in terms of carbenium ion mechanisms. Conditions were chosen to minimize bimol. reactions. Cracking rates increase more dramatically with carbon no. for olefins than for monomol. cracking of paraffins, as more energetically favorable modes become available for β-scission, as classified by the types of carbenium ions involved. For hexene and heptene feeds, the most-favorable β-scission mode available (C-type, involving just secondary carbenium ions, for hexene feed; B-type, involving secondary plus tertiary carbenium ions for heptene) accounted for 70-80% of the cracking. Product distribution was independent of which hexene or heptene isomer was fed, since double-bond and skeletal isomerization precedes significant cracking. For 1-octene feed, however, the olefin was nearly all cracked via secondary-tertiary and tertiary-secondary β-scission (after isomerizing to a dimethylhexene) before it isomerized further to the 2,4,4-trimethylpentene isomer, which would be required to undergo the most energetically favored (tertiary-tertiary) form of cracking. A semiquant. prediction of rates and product distribution for 1-octene cracking could be made, using rates for the various types of β-scission calcd. from results with C6-C7 feeds.
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    64. 64
      Van Speybroeck, V.; De Wispelaere, K.; Van der Mynsbrugge, J.; Vandichel, M.; Hemelsoet, K.; Waroquier, M. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study. Chem. Soc. Rev. 2014, 43, 7326– 7357,  DOI: 10.1039/C4CS00146J
      Google Scholar
      64
      First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study
      Van Speybroeck, Veronique; De Wispelaere, Kristof; Van der Mynsbrugge, Jeroen; Vandichel, Matthias; Hemelsoet, Karen; Waroquier, Michel
      Chemical Society Reviews (2014), 43 (21), 7326-7357CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      To optimally design next generation catalysts a thorough understanding of the chem. phenomena at the mol. scale is a prerequisite. Apart from qual. knowledge on the reaction mechanism, it is also essential to be able to predict accurate rate consts. Mol. modeling has become a ubiquitous tool within the field of heterogeneous catalysis. Herein, we review current computational procedures to det. chem. kinetics from first principles, thus by using no exptl. input and by modeling the catalyst and reacting species at the mol. level. Therefore, we use the methanol-to-olefin (MTO) process as a case study to illustrate the various theor. concepts. This process is a showcase example where rational design of the catalyst was for a long time performed on the basis of trial and error, due to insufficient knowledge of the mechanism. For theoreticians the MTO process is particularly challenging as the catalyst has an inherent supramol. nature, for which not only the Bronsted acidic site is important but also org. species, trapped in the zeolite pores, must be essentially present during active catalyst operation. All these aspects give rise to specific challenges for theor. modeling. It is shown that present computational techniques have matured to a level where accurate enthalpy barriers and rate consts. can be predicted for reactions occurring at a single active site. The comparison with exptl. data such as apparent kinetic data for well-defined elementary reactions has become feasible as current computational techniques also allow predicting adsorption enthalpies with reasonable accuracy. Real catalysts are truly heterogeneous in a space- and time-like manner. Future theory developments should focus on extending our view towards phenomena occurring at longer length and time scales and integrating information from various scales towards a unified understanding of the catalyst. Within this respect mol. dynamics methods complemented with addnl. techniques to simulate rare events are now gradually making their entrance within zeolite catalysis. Recent applications have already given a flavor of the benefit of such techniques to simulate chem. reactions in complex mol. environments.
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    65. 65
      Haag, W. O.; Lago, R. M.; Rodewald, P. G. Aromatics, light olefins and gasoline from methanol: Mechanistic pathways with ZSM-5 zeolite catalyst. J. Mol. Catal. 1982, 17, 161– 169,  DOI: 10.1016/0304-5102(82)85027-X
      Google Scholar
      65
      Aromatics, light olefins and gasoline from methanol: mechanistic pathways with ZSM-5 zeolite catalyst
      Haag, W. O.; Lago, R. M.; Rodewald, P. G.
      Journal of Molecular Catalysis (1982), 17 (2-3), 161-9CODEN: JMCADS; ISSN:0304-5102.
      The conversion of MeOH [67-56-1] to hydrocarbons with zeolite ZSM-5 as catalyst provides a novel route to gasoline as well as to olefins and aroms. as chem. raw materials. The reaction is acid-catalyzed and involves alkylation of olefins and aroms. as major MeOH conversion steps, accompanied by olefin isomerization, polymn./cracking, cyclization and aromatization via H transfer. Shape-selective control of the aroms. produced results from the use of the medium pore size zeolite ZSM-5. The true kinetic paths are often disguised by diffusion/desorption effects. C2H4 is most likely the first olefinic hydrocarbon formed.
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    66. 66
      Abbot, J.; Corma, A.; Wojciechowski, B. W. The catalytic isomerization of 1-hexene on H-ZSM-5 zeolite: The effects of a shape-selective catalyst. J. Catal. 1985, 92, 398– 408,  DOI: 10.1016/0021-9517(85)90273-8
      Google Scholar
      66
      The catalytic isomerization of 1-hexene on H-ZSM-5 zeolite: the effects of a shape-selective catalyst
      Abbot, J.; Corma, A.; Wojciechowski, B. W.
      Journal of Catalysis (1985), 92 (2), 398-408CODEN: JCTLA5; ISSN:0021-9517.
      The isomerization of 1-hexene on 60/80-mesh ZSM-5 zeolite was studied at 200-280°, and the results were compared with those previously obtained for HY at 200°. The obsd. products were formed through a variety of processes including double bond shift, cis-trans isomerization, skeletal rearrangement, cracking, hydrogen transfer, polymn., and coke formation. By applying the time-on-stream theory, the products were classified as primary, secondary, or both according to their optimum performance envelope curves on product selectivity plots. At all levels of conversion, cis- and trans-2-hexene were the principal products. The ratio of the initial selectivities of cis- to trans-2-hexene at 200° was 0.54, significantly closer to the equil. value than previously found for HY zeolite. A possible explanation is given, relating to the difference in pore structure of these zeolites. The ratio of the initial rate of deprotonation to that of hydrogen shift in the hexyl carbenium ion was found to decrease with temp. At 200° this ratio was greater that that obsd. on HY. Skeletal rearrangement, polymn., cracking, and hydrogen transfer reactions all increase with temp. At 200° the total contribution from these processes accounts for significantly less product than on HY. All products of skeletal rearrangement were obsd. to be secondary. The formation of 2,3-dimethyl-1-butene appears to be restricted on ZSM-5 due to the size of this mol. Skeletal rearrangement of 1-hexene gives cis-3-methyl-2-pentene and trans-3-methyl-2-pentene as secondary products. These isomers are also formed as initial products by double bond shift of the principal impurity present in the feed, 2-ethyl-1-butene. Coke formation decreases with increasing temp. The compn. of the coke indicated that it initially consists mainly of adsorbed olefins. No arom. products could be detected and polymn. appeared to be restricted to the formation of dimers. The small amt. of paraffinic products found, and the lack of cyclization and dehydrogenation to arom. structures appear to be related to the pore size of ZSM-5.
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    67. 67
      Abbot, J.; Wojciechowski, B. W. Catalytic cracking and skeletal isomerization of n-Hexene on ZSM-5 Zeolite. Can. J. Chem. Eng. 1985, 63, 451– 461,  DOI: 10.1002/cjce.5450630314
      Google Scholar
      67
      Catalytic cracking and skeletal isomerization of n-hexene on ZSM-5 zeolite
      Abbot, J.; Wojciechowski, B. W.
      Canadian Journal of Chemical Engineering (1985), 63 (3), 451-61CODEN: CJCEA7; ISSN:0008-4034.
      With respect to coke formation in petroleum cracking and MeOH conversion to gasoline, the catalytic cracking and skeletal isomerization of hexene [25264-93-1] on ZSM-5 zeolite were studied at 350-405°. By applying the time-on-stream theory, the products of the reaction were identified as primary, secondary, or both according to their optimum performance envelope (OPE) curves on product selectivity plots. The products of cracking were almost exclusively monoolefins, of which the C3-5 olefins were stable primary or primary plus secondary products. No CH4 was found; only traces of C2 products (as C2H4) were obsd. The obsd. product distributions can be explained by a dimerization-cracking mechanism with no product species having more than twelve carbon atoms. The probability of a fragment undergoing further cracking before desorption increased with temp. and the obsd. initial selectivities must be cor. to account for this process. Methylpentene (I) [37275-41-5], formed as an unstable primary product, was the main isomer produced by skeletal rearrangement; those isomers of I derived from more stable carbenium ions predominated.
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    68. 68
      Kissin, Y. V. Chemical Mechanism of Hydrocarbon Cracking over Solid Acidic Catalysts. J. Catal. 1996, 163, 50– 62,  DOI: 10.1006/jcat.1996.0304
      Google Scholar
      68
      Chemical mechanism of hydrocarbon cracking over solid acidic catalysts
      Kissin, Yury V.
      Journal of Catalysis (1996), 163 (1), 50-62CODEN: JCTLA5; ISSN:0021-9517. (Academic)
      The article analyzes cracking reactions of isoalkanes and isoolefins over zeolite-based catalysts and discuss formation mechanisms of light reaction products under very mild conditions at 150-250°C. Cracking patterns of 28 methyl- and ethyl-branched isoalkanes show that the compns. of light products can be described by an empirical rule: (1) the reaction site is formed at the tertiary carbon atom in an isoalkane mol., (2) the predominant fission reaction involves the weakest C-C bond in the α-position to the reaction site, (3) the primary fission products are olefins. None of the cracking mechanisms described in the literature and involving reactions of carbenium and carbonium ions can adequately predict the obsd. product structures. A new cracking mechanism of isoalkanes which includes reactions between isoalkanes and Bronsted centers on the catalyst surface with the formation of transient hydrosiloxonium ions>Si-O+ (H)-C< is proposed. The ions undergo the scission of the C-C bond in their alkyl groups in the β-position to O+ with the formation of olefin mols. (which rapidly isomerize) and smaller hydrosiloxonium ions. Comparison of cracked products from olefins and alkanes with the same skeletons and the same expected carbocations shows that the resp. products are drastically different when they are formed under very mild conditions, i.e., that the cracking mechanisms of olefins and alkanes are also different. Studies of olefins with low oligomerization abilities (to prevent scrambling of the product structures) show that the olefin cracking can indeed be explained by fragmentation of carbenium ions via the β-C bond scission mechanism.
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    69. 69
      Cnudde, P.; De Wispelaere, K.; Van der Mynsbrugge, J.; Waroquier, M.; Van Speybroeck, V. Effect of temperature and branching on the nature and stability of alkene cracking intermediates in H-ZSM-5. J. Catal. 2017, 345, 53– 69,  DOI: 10.1016/j.jcat.2016.11.010
      Google Scholar
      69
      Effect of temperature and branching on the nature and stability of alkene cracking intermediates in H-ZSM-5
      Cnudde, P.; De Wispelaere, K.; Van der Mynsbrugge, J.; Waroquier, M.; Van Speybroeck, V.
      Journal of Catalysis (2017), 345 (), 53-69CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      Catalytic cracking of alkenes takes place at elevated temps. in the order of 773-833 K. In this work, the nature of the reactive intermediates at typical reaction conditions is studied in H-ZSM-5 using a complementary set of modeling tools. Ab initio static and mol. dynamics simulations are performed on different C4-C5 alkene cracking intermediates to identify the reactive species in terms of temp. At 323 K, the prevalent intermediates are linear alkoxides, alkene π-complexes and tertiary carbenium ions. At a typical cracking temp. of 773 K, however, both secondary and tertiary alkoxides are unlikely to exist in the zeolite channels. Instead, more stable carbenium ion intermediates are found. Branched tertiary carbenium ions are very stable, while linear carbenium ions are predicted to be metastable at high temp. Our findings confirm that carbenium ions, rather than alkoxides, are reactive intermediates in catalytic alkene cracking at 773 K.
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    70. 70
      Hajek, J.; Van der Mynsbrugge, J.; De wispelaere, K.; Cnudde, P.; Vanduyfhuys, L.; Waroquier, M.; Van Speybroeck, V. On the stability and nature of adsorbed pentene in Brønsted acid zeolite H-ZSM-5 at 323 K. J. Catal. 2016, 340, 227– 235,  DOI: 10.1016/j.jcat.2016.05.018
      Google Scholar
      70
      On the stability and nature of adsorbed pentene in Bronsted acid zeolite H-ZSM-5 at 323 K
      Hajek, J.; Van der Mynsbrugge, J.; De Wispelaere, K.; Cnudde, P.; Vanduyfhuys, L.; Waroquier, M.; Van Speybroeck, V.
      Journal of Catalysis (2016), 340 (), 227-235CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      Adsorption of linear pentenes in H-ZSM-5 at 323 K is investigated using contemporary static and mol. dynamics methods. A physisorbed complex corresponding to free pentene, a π-complex and a chemisorbed species may occur. The chemisorbed species can be either a covalently bonded alkoxide or an ion pair, the so-called carbenium ion. Without finite temp. effects, the π-complex is systematically slightly more bound than the chemisorbed alkoxide complex, whereas mol. dynamics calcns. at 323 K yield an almost equal stability of both species. The carbenium ion was not obsd. during simulations at 323 K. The transformation from the π-complex to the chemisorbed complex is activated by a free energy in the range of 33-42 kJ/mol. Our observations yield unprecedented insights into the stability of elusive intermediates in zeolite catalysis, for which exptl. data are very hard to measure.
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    71. 71
      Bučko, T.; Benco, L.; Hafner, J.; Ángyán, J. G. Monomolecular cracking of propane over acidic chabazite: An ab initio molecular dynamics and transition path sampling study. J. Catal. 2011, 279, 220– 228,  DOI: 10.1016/j.jcat.2011.01.022
      Google Scholar
      71
      Monomolecular cracking of propane over acidic chabazite: An ab initio molecular dynamics and transition path sampling study
      Bucko, Tomas; Benco, Lubomir; Hafner, Juergen; Angyan, Janos G.
      Journal of Catalysis (2011), 279 (1), 220-228CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      The monomol. Haag-Dessau mechanism for propane cracking over acidic chabazite has been studied using dispersion-cor. periodic DFT calcns. in combination with ab initio mol. dynamics (AIMD) simulations, transition path sampling (TPS), and free-energy integrations. The AIMD simulations show that due to the weak specific interaction of the satd. mol. with Bronsted acid sites, the adsorption energy is considerably reduced at elevated temp. and that only a fraction of the mols. adsorbed within the zeolite is sufficiently close to the acid site to form a reactant complex for protonation. TPS shows that the preferred reaction mechanism is the protonation of a terminal Me group. The direct proton attack on the C-C bond between the Me and methylene groups is not excluded but occurs with lower probability. The intrinsic reaction parameters such as free energy and entropy of activation are detd. using thermodn. integration based on constrained mol. dynamics simulations.
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    72. 72
      Zimmerman, P. M.; Tranca, D. C.; Gomes, J.; Lambrecht, D. S.; Head-Gordon, M.; Bell, A. T. Ab Initio Simulations Reveal that Reaction Dynamics Strongly Affect Product Selectivity for the Cracking of Alkanes over H-MFI. J. Am. Chem. Soc. 2012, 134, 19468– 19476,  DOI: 10.1021/ja3089372
      Google Scholar
      72
      Ab Initio Simulations Reveal that Reaction Dynamics Strongly Affect Product Selectivity for the Cracking of Alkanes over H-MFI
      Zimmerman, Paul M.; Tranca, Diana C.; Gomes, Joseph; Lambrecht, Daniel S.; Head-Gordon, Martin; Bell, Alexis T.
      Journal of the American Chemical Society (2012), 134 (47), 19468-19476CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Product selectivity of alkane cracking catalysis in the H-MFI zeolite is investigated using both static and dynamic first-principles quantum mechanics/mol. mechanics simulations. These simulations account for the electrostatic- and shape-selective interactions in the zeolite and provide enthalpic barriers that are closely comparable to expt. Cracking transition states for n-pentane lead to a metastable intermediate (a local min. with relatively small barriers to escape to deeper min.) where the proton is shared between two hydrocarbon fragments. The zeolite strongly stabilizes these carbocations compared to the gas phase, and the conversion of this intermediate to more stable species dets. the product selectivity. Static reaction pathways on the potential energy surface starting from the metastable intermediate include a variety of possible conversions into more stable products. One-picosecond quasiclassical trajectory simulations performed at 773 K indicate that dynamic paths are substantially more diverse than the potential energy paths. Vibrational motion that is dynamically sampled after the cracking transition state causes spilling of the metastable intermediate into a variety of different products. A nearly 10-fold change in the branching ratio between C2/C3 cracking channels is found upon inclusion of post-transition-state dynamics, relative to static electronic structure calcns. Agreement with expt. is improved by the same factor. Because dynamical effects occur soon after passing through the rate-limiting transition state, it is the dynamics, and not only the potential energy barriers, that det. the catalytic selectivity. This study suggests that selectivity in zeolite catalysis is detd. by high temp. pathways that differ significantly from 0 K potential surfaces.
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    73. 73
      Gounder, R.; Iglesia, E. Catalytic Consequences of Spatial Constraints and Acid Site Location for Monomolecular Alkane Activation on Zeolites. J. Am. Chem. Soc. 2009, 131, 1958– 1971,  DOI: 10.1021/ja808292c
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      73
      Catalytic Consequences of Spatial Constraints and Acid Site Location for Monomolecular Alkane Activation on Zeolites
      Gounder, Rajamani; Iglesia, Enrique
      Journal of the American Chemical Society (2009), 131 (5), 1958-1971CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      The location of Bronsted acid sites within zeolite channels strongly influences reactivity because of the extent to which spatial constraints det. the stability of reactants and of cationic transition states relevant to alkane activation catalysis. Turnover rates for monomol. cracking and dehydrogenation of propane and n-butane differed among zeolites with varying channel structure (H-MFI, H-FER, H-MOR) and between OH groups within eight-membered ring (8-MR) side pockets and 12-MR main channels in H-MOR. Measured monomol. alkane activation barriers depended on catalyst and reactant properties, such as deprotonation enthalpies and proton affinities, resp., consistent with Born-Haber thermochem. cycles that define energy relations in acid catalysis. Monomol. alkane cracking and dehydrogenation turnovers occurred with strong preference on acid sites contained within smaller 8-MR pockets in H-MOR, while rates on sites located within 12-MR channels were much lower and often undetectable. This strong specificity reflects transition states that are confined only partially within 8-MR pockets; as a result, entropic gains compensate for enthalpic penalties caused by their incomplete containment to give a lower free energy for transition states within small 8-MR side pockets. These effects of entropy are stronger for dehydrogenation, with a later and looser transition state, than for cracking in the case of both propane and n-butane; therefore, selectivity can be tuned by the selective positioning or titrn. of OH groups within specific environments, the no. of which was assessed in H-MOR by rigorous deconvolution of their IR spectra. Specifically, cracking-to-dehydrogenation ratios for propane and n-butane were much smaller and terminal-to-central C-C bond cleavage ratios for n-butane were much larger on 8-MR than on 12-MR acid sites as a result of partial confinement, a concept previously considered phenomenol. as pore mouth catalysis. These marked effects of spatial constraints and of entropic factors on acid site reactivity and selectivity, also inferred for MFI from titrn. of OH groups by Na+, have not been previously proposed or recognized and appear to be unprecedented in hydrocarbon catalysis. These findings and their conceptual interpretations open opportunities for the design of microporous solids by the rational positioning of acid sites within specific channel locations and with predictable consequences for catalytic rates and selectivities.
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    74. 74
      Gounder, R.; Iglesia, E. Effects of Partial Confinement on the Specificity of Monomolecular Alkane Reactions for Acid Sites in Side Pockets of Mordenite. Angew. Chem., Int. Ed. 2010, 49, 808– 811,  DOI: 10.1002/anie.200905869
      Google Scholar
      74
      Effects of Partial Confinement on the Specificity of Monomolecular Alkane Reactions for Acid Sites in Side Pockets of Mordenite
      Gounder, Rajamani; Iglesia, Enrique
      Angewandte Chemie, International Edition (2010), 49 (4), 808-811, S808/1-S808/13CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Isobutane cracking has a stronger preference for reaction within eight-membered ring (8-MR) side pockets in mordenite zeolite (MOR) than does dehydrogenation, in sharp contrast with the trends for n-alkane reactions. Transition state energies are higher for isobutane cracking than for dehydrogenation, consistent with the less stable cations formed upon protonation of C-C bonds instead of the tertiary C-H bond in isobutane. As for monomol. n-alkane dehydrogenation, isobutane cracking shows a stronger preference for reaction on 8-MR acid sites than does dehydrogenation because it involves later and looser transition states, which benefit more strongly from entropy gains arising from partial confinement.
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    75. 75
      Sarazen, M. L.; Doskocil, E.; Iglesia, E. Catalysis on solid acids: Mechanism and catalyst descriptors in oligomerization reactions of light alkenes. J. Catal. 2016, 344, 553– 569,  DOI: 10.1016/j.jcat.2016.10.010
      Google Scholar
      75
      Catalysis on solid acids: Mechanism and catalyst descriptors in oligomerization reactions of light alkenes
      Sarazen, Michele L.; Doskocil, Eric; Iglesia, Enrique
      Journal of Catalysis (2016), 344 (), 553-569CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      This study addresses fundamental descriptions of confinement and acid strength effects on stability for transition states and intermediates involved in alkene oligomerization on solid acids. Kinetic and IR data and theor. treatments that account for dispersive interactions show that turnover rates (per H+) on aluminosilicates and heterosilicates with microporous voids (TON, MFI, BEA, FAU) and on mesoporous acids (amorphous silica-alumina, dispersed polyoxometalates) reflect the free energy of C-C bond formation transition states referenced to gaseous alkenes and bound alkene-derived precursors present at satn. coverages. These free energy barriers decrease as the size of confining voids decreases in aluminosilicates contg. acid sites of similar acid strength and approaches bimol. transition state (TS) sizes derived from d. functional theory (DFT) for propene and isobutene reactants. Such TS structures are preferentially stabilized over smaller bound precursors via contacts with the confining framework. These effects of size, typically based on heuristic geometric analogies, are described here instead by the dispersive component of DFT-derived energies for TS and intermediates, which bring together the effects of size and the shape, for different framework voids and TS and precursor structures derived from alkenes of different size; these org. moieties differ in "fit" within voids but also in their proton affinity, as a result of the ion-pair character of TS structures. The larger charge in TS structures relative to their alkene-derived precursors causes free energy barriers to decrease as conjugate anions become more stable in stronger acids. Consequently, oligomerization rate consts. decrease exponentially with increasing deprotonation energy on unconfined acid sites in polyoxometalates and silica-alumina and on confined sites within MFI frameworks with Al, Ga, Fe, or B heteroatoms. Reactivity descriptions based on geometry or acid strength are replaced by their more relevant energetic descriptors-van der Waals confinement energies, proton affinities of org. mols., and deprotonation energies-to account for reactivity, here for different reactants on diverse solid acids, but in general for acid catalysis.
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    76. 76
      Sarazen, M. L.; Iglesia, E. Stability of bound species during alkene reactions on solid acids. Proc. Natl. Acad. Sci. U. S. A. 2017, 114, E3900– E3908,  DOI: 10.1073/pnas.1619557114
      Google Scholar
      76
      Stability of bound species during alkene reactions on solid acids
      Sarazen, Michele L.; Iglesia, Enrique
      Proceedings of the National Academy of Sciences of the United States of America (2017), 114 (20), E3900-E3908CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)
      This study reports the thermodn. of bound species derived from ethene, propene, n-butene, and isobutene on solid acids with diverse strength and confining voids. D. functional theory (DFT) and kinetic data indicate that covalently bound alkoxides form C-C bonds in the kinetically relevant step for dimerization turnovers on protons within TON (0.57 nm) and MOR (0.67 nm) zeolitic channels and on stronger acids HPW (polyoxometalate clusters on silica). Turnover rates for mixed alkenes give relative alkoxide stabilities; the resp. adsorption consts. are obtained from in situ IR spectra. Tertiary alkoxides (from isobutene) within larger voids (MOR, HPW) are more stable than less substituted isomers but are destabilized within smaller concave environments (TON) because framework distortions are required to avoid steric repulsion. Adsorption consts. are similar on MOR and HPW for each alkoxide, indicating that binding is insensitive to acid strength for covalently bound species. DFT-derived formation free energies for alkoxides with different framework attachments and backbone length/structure agree with measurements when dispersion forces, which mediate stabilization by confinement in host-guest systems, are considered. Theory reveals previously unrecognized framework distortions that balance the C-O bond lengths required for covalency with host-guest distances that maximize van der Waals contacts. These distortions, reported here as changes in O-atom locations and dihedral angles, become stronger for larger, more substituted alkoxides. The thermodn. properties reported here for alkoxides and acid hosts differing in size and conjugate-anion stability are benchmarked against DFT-derived free energies; their details are essential to design host-guest pairs that direct alkoxide species toward specific products.
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    77. 77
      De Moor, B. A.; Reyniers, M. F.; Gobin, O. C.; Lercher, J. A.; Marin, G. B. Adsorption of C2–C8 n-Alkanes in Zeolites. J. Phys. Chem. C 2011, 115, 1204– 1219,  DOI: 10.1021/jp106536m
      Google Scholar
      77
      Adsorption of C2-C8 n-Alkanes in Zeolites
      De Moor, Bart A.; Reyniers, Marie-Francoise; Gobin, Oliver C.; Lercher, Johannes A.; Marin, Guy B.
      Journal of Physical Chemistry C (2011), 115 (4), 1204-1219CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      Adsorption of n-alkanes has been studied in the industrially relevant zeolites H-FAU, H-BEA, H-MOR, and H-ZSM-5 combining QM-Pot(MP2//B3LYP) with statistical thermodn. calcns. and assuming a mobile adsorbate. In H-ZSM-5, adsorption at the intersection site with the hydrocarbon chain extending in the straight channel (SC+I) as well as in the zigzag channel (ZC+I) has been studied. In addn., differential heats of adsorption and adsorption isotherms at temps. from 301 to 400 K of all C3-C6 n-alkane in H-ZSM-5 have been measured simultaneously via calorimetry and gravimetry. Calcd. adsorption enthalpies are independent of temp. and are virtually identical to the adsorption energies. The adsorption strength increases in the order H-FAU < H-BEA < H-MOR < H-ZSM-5 (SC+I) < H-ZSM-5 (ZC+I) and varies linearly with the carbon no. As compared to exptl. values, the calcd. adsorption strength is overestimated by some 2 kJ mol-1/CH2 in FAU up to some 4 kJ mol-1/CH2 in H-ZSM-5 suggesting that the QM-Pot(MP2//B3LYP) calcns. overestimate van der Waals stabilizing interactions and a correction term has been proposed. Adsorption entropy losses are independent of temp. and increase in the order H-FAU < H-BEA < H-MOR < H-ZSM-5 (SC+I) < H-ZSM-5 (ZC+I), according to the pore size of the zeolites. The calcd. adsorption entropies agree nicely with available exptl. results in all zeolites. QM-Pot(MP2//B3LYP) calcd. adsorption equil. coeffs. (using the cor. adsorption enthalpies) correspond relatively well to exptl. detd. values. Comparison of relative turnover frequencies with relative adsorption equil. coeffs. indicates that the variation of the equil. coeff. with the carbon no. or with the zeolite can only partly explain the obsd. reactivity differences in monomol. cracking of n-alkanes. In agreement with exptl. observations, our results indicate that the difference in reactivity of the n-alkanes for monomol. cracking in a given zeolite mainly originates from a difference in intrinsic monomol. cracking rate coeffs.
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    78. 78
      Nguyen, C. M.; De Moor, B. A.; Reyniers, M. F.; Marin, G. B. Isobutene Protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22. J. Phys. Chem. C 2012, 116, 18236– 18249,  DOI: 10.1021/jp304081k
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      78
      Isobutene Protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22
      Nguyen, Cuong M.; De Moor, Bart A.; Reyniers, Marie-Francoise; Marin, Guy B.
      Journal of Physical Chemistry C (2012), 116 (34), 18236-18249CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      Kinetics and thermodn. of isobutene protonation in H-FAU, H-MOR, H-ZSM-5, and H-ZSM-22 were studied at 300-800 K, combining PW91-D//PW91 periodic d. functional theory calcns. with statistical thermodn. At temps. relevant for industrial zeolite-catalyzed processes (500-800 K), the tert-Bu carbenium ion is more stable than the tert-butoxy in H-MOR, H-ZSM-5, and H-ZSM-22. Entropy contributions govern the std. Gibbs free energy stability of the chemisorbed intermediates. Due to the absence of a C-O covalent bond, formation of the tert-Bu carbenium ion is accompanied by a lower entropy loss and, consequently, has a higher stability than the tert-butoxy in H-MOR, H-ZSM-5, and H-ZSM-22. At 800 K, the protonation toward tert-butoxy in H-FAU, H-MOR, and H-ZSM-5 and to the tert-Bu carbenium ion in H-ZSM-22 is 5 to 7 orders of magnitude faster than the protonation toward isobutoxy. Among the four zeolites, the lowest activation energy is found in H-ZSM-22.
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    79. 79
      Bučko, T.; Hafner, J. The role of spatial constraints and entropy in the adsorption and transformation of hydrocarbons catalyzed by zeolites. J. Catal. 2015, 329, 32– 48,  DOI: 10.1016/j.jcat.2015.04.015
      Google Scholar
      79
      Role of spatial constraints and entropy in adsorption and transformation of hydrocarbon cracking catalyzed by zeolites
      Bucko, Tomas; Hafner, Jurgen
      Journal of Catalysis (2015), 329 (), 32-48CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)
      The competing influences of enthalpy and entropy on the adsorption and transformation of hydrocarbon mols. in zeolites have been investigated using dispersion-cor. d.-functional theory in combination with advanced statistical-mech. techniques. At the example of propane in protonated mordenite, it is demonstrated that while enthalpy favors adsorption in the narrower side pockets (SP) due to the stronger interaction with the framework, the loss of entropy is smaller for mols. in the wider main channel (MC). At ambient and elevated temps., the free energy favors adsorption in the MC (in agreement with expt.) and diffusion to the SP is an activated process. On the other hand, the free energy of activation for monomol. cracking is lower for Bronsted acid (BA) sites in the SP, if the reactant is already located there. Cracking at a BA in the MC is a simple one-step reaction but as the SP is accessible to mols. only via the MC, cracking at a BA site in the SP is possible only after overcoming the barrier for diffusion from the MC to the SP. Thus, the difference in the free energies of adsorption in the MC and the SP increases the effective free-energy of activation for the reaction in SP and the reaction in the MC is favored. This result contradicts the interpretation of recent expts. on hydrocarbon transformations catalyzed by mordenite-contg. BA sites and Na+ counterions in varying proportions. This exptl. interpretation is based on the assumption that Na+ counterions preferentially replace BA sites located in the SP. This assumption has been critically examd. using ab-initio calcns. and found to be inconsistent with our theor. predictions. It is demonstrated that the exptl. obsd. decrease of the reaction rate with increasing Na+/H+ ratio arises from the strongly attractive nature of the Na+ counterions, which makes the approach of the reactant to the BA site more difficult and reduces the reaction rate. We suggest that our results on the competing influence of enthalpy and entropy arising from the confinement of the reactant in cavities of different diams. have general validity for the adsorption and acid-catalyzed reactions of hydrocarbon mols. in zeolites with a complex framework structure.
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    80. 80
      Janda, A.; Vlaisavljevich, B.; Lin, L. C.; Smit, B.; Bell, A. T. Effects of Zeolite Structural Confinement on Adsorption Thermodynamics and Reaction Kinetics for Monomolecular Cracking and Dehydrogenation of n-Butane. J. Am. Chem. Soc. 2016, 138, 4739– 4756,  DOI: 10.1021/jacs.5b11355
      Google Scholar
      80
      Effects of Zeolite Structural Confinement on Adsorption Thermodynamics and Reaction Kinetics for Monomolecular Cracking and Dehydrogenation of n-Butane
      Janda, Amber; Vlaisavljevich, Bess; Lin, Li-Chiang; Smit, Berend; Bell, Alexis T.
      Journal of the American Chemical Society (2016), 138 (14), 4739-4756CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      The effects of zeolite structure on the kinetics of n-butane monomol. cracking and dehydrogenation are investigated for eight zeolites differing in the topol. of channels and cages. Monte Carlo simulations are used to calc. enthalpy and entropy changes for adsorption (ΔHads-H+ and ΔSads-H+) of gas-phase alkanes onto Bronsted protons. These parameters are used to ext. intrinsic activation enthalpies (ΔH‡int), entropies (ΔS‡int), and rate coeffs. (kint) from measured data. As ΔSads-H+ decreases (i.e., as confinement increases), ΔH‡int and ΔS‡int for terminal cracking and dehydrogenation decrease for a given channel topol. These results, together with pos. values obsd. for ΔS‡int, indicate that the transition states for these reactions resemble products. For central cracking (an earlier transition state), ΔH‡int is relatively const., while ΔS‡int increases as ΔSads-H+ decreases because less entropy is lost upon protonation of the alkane. Concurrently, selectivities to terminal cracking and dehydrogenation decrease relative to central cracking because ΔS‡int decreases for the former reactions. Depending on channel topol., changes in the measured rate coeffs. (kapp) with confinement are driven by changes in kint or by changes in the adsorption equil. const. (Kads-H+). Values of ΔS‡int and ΔH‡int are pos. correlated, consistent with weaker interactions between the zeolite and transition state and with the greater freedom of movement of product fragments within more spacious pores. These results differ from earlier reports that ΔH‡int and ΔS‡int are structure-insensitive and that kapp is dominated by Kads-H+. They also suggest that ΔSads-H+ is a meaningful descriptor of confinement for zeolites having similar channel topologies.
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    81. 81
      Dutta Chowdhury, A.; Gascon, J. The Curious Case of Ketene in Zeolite Chemistry and Catalysis. Angew. Chem., Int. Ed. 2018, 57, 14982– 14985,  DOI: 10.1002/anie.201808480
      Google Scholar
      There is no corresponding record for this reference.
    82. 82
      Kuei, C. K.; Lee, M. D. Hydrogenation of Carbon Dioxide by Hybrid Catalysts, Direct Synthesis of Aromatics from Carbon Dioxide and Hydrogen. Can. J. Chem. Eng. 1991, 69, 347– 354,  DOI: 10.1002/cjce.5450690142
      Google Scholar
      82
      Hydrogenation of carbon dioxide by hybrid catalysts, direct synthesis of aromatics from carbon dioxide and hydrogen
      Kuei, Chi Kung; Lee, Min Dar
      Canadian Journal of Chemical Engineering (1991), 69 (1), 347-54CODEN: CJCEA7; ISSN:0008-4034.
      Direct synthesis of aroms. from CO2 hydrogenation was investigated in a single stage reactor by using hybrid catalysts composed of Fe catalysts and HZSM-5 zeolite. CO2 was first converted to CO by the reverse water gas shift reaction, followed by the hydrogenation of CO to hydrocarbons on Fe catalyst, and finally the hydrocarbons were converted to aroms. in HZSM-5. Under the operating conditions of 350°, 2100 kPa, and CO2/H = 1/2, the max. arom. selectivity obtained was 22% with a CO2 conversion of 38% by using fused Fe catalyst combined with the zeolite. Together with the kinetic studies, thermodn. anal. of the CO2 hydrogenation was also conducted. Unlike Fischer Tropsch synthesis, the formation of hydrocarbons from CO2 may not be thermodynamically favored at higher temps.
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    83. 83
      Fujiwara, M.; Ando, H.; Tanaka, M.; Souma, Y. Hydrogenation of Carbon Dioxide over Cu-Zn-Chromate/Zeolite Composite Catalyst: The Effects of Reaction Behavior of Alkenes on Hydrocarbon Synthesis. Appl. Catal., A 1995, 130, 105– 116,  DOI: 10.1016/0926-860X(95)00108-5
      Google Scholar
      83
      Hydrogenation of carbon dioxide over Cu-Zn-chromate/zeolite composite catalyst: The effects of reaction behavior of alkenes on hydrocarbon synthesis
      Fujiwara, Masahiro; Ando, Hisanori; Tanaka, Mutsuo; Souma, Yoshie
      Applied Catalysis, A: General (1995), 130 (1), 105-16CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
      The hydrogenation of carbon dioxide was studied using composite catalysts comprised of Cu-Zn-chromate and HY zeolite. These composite catalysts enabled the reaction combining methanol synthesis and methanol-to-gasoline reaction, and achieved the formation of ethylene and propene as the first example of the composite catalysts. The addn. of alk. metals, esp. cesium, to Cu-Zn-chromate enhanced the selectivities of those alkenes. The influences of the reaction pressure and the space velocity on the prodn. of alkenes show that alkanes are obtained by the hydrogenation of the corresponding alkenes. The composite catalysts producing alkenes in high selectivity afforded heavier hydrocarbons preferentially. These results indicate that the hydrogenation of alkenes inhibits the carbon homologation of alkenes to result in the predominant formation of the corresponding lighter alkanes. From these observations, methanol synthesis catalysts used for the composite catalysts are required to be effective for methanol synthesis at high temp. (over 300°) and to bear the low activity of the hydrogenation of alkenes.
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    84. 84
      Fujiwara, M.; Kieffer, R.; Ando, H.; Xu, Q.; Souma, Y. Change of Catalytic Properties of FeZnO/Zeolite Composite Catalyst in the Hydrogenation of Carbon Dioxide. Appl. Catal., A 1997, 154, 87– 101,  DOI: 10.1016/S0926-860X(96)00360-2
      Google Scholar
      84
      Change of catalytic properties of Fe-ZnO/zeolite composite catalyst in the hydrogenation of carbon dioxide
      Fujiwara, Masahiro; Kieffer, Roger; Ando, Hisanori; Xu, Qiang; Souma, Yoshie
      Applied Catalysis, A: General (1997), 154 (1-2), 87-101CODEN: ACAGE4; ISSN:0926-860X. (Elsevier)
      The hydrogenation of carbon dioxide was examd. using the composite catalysts which were obtained by the phys. mixing of Fe-ZnO and HY zeolite. Fe-ZnO was a typical F-T (Fischer-Tropsch) catalyst and Fe-ZnO/HY is a composite catalyst which is able to induce a combined methanol synthesis and MTG (Methanol-to-Gasoline) reaction. To study these unique catalytic behaviors of Fe-ZnO/HY, the adsorption and the dissocn. of carbon monoxide on Fe-ZnO as well as TPR measurements were carried out. Fe-ZnO is able to produce hydrocarbons by F-T reaction and methanol. In the absence of zeolite, Fe-ZnO exerts its ability for F-T reaction. However, HY diminishes the activity for F-T reaction and hydrocarbons were obtained via methanol formed over the modified Fe-ZnO.
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    85. 85
      Kim, H.; Choi, D. H.; Nam, S. S.; Choi, M. J.; Lee, K. W. The Selective Synthesis of Lower Olefins (C2 - C4) by the CO2 Hydrogenation over Iron Catalysts Promoted with Potassium and Supported on Ion Exchanged (H, K) Zeolite-Y. Stud. Surf. Sci. Catal. 1998, 114, 407– 410,  DOI: 10.1016/S0167-2991(98)80782-9
      Google Scholar
      85
      The selective synthesis of lower olefins (C2 - C4) by the CO2 hydrogenation over iron catalysts promoted with potassium and supported on ion exchanged (H, K) zeolite-Y
      Kim, Ho; Choi, Dae-Ho; Nam, Sang-Sung; Choi, Myung-Jae; Lee, Kyu-Wan
      Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 407-410CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
      Selective for lower olefins (C2-C4) in carbon dioxide hydrogenation over zeolite-supported iron catalysts promoted with potassium is increased when potassium-exchanged zeolite is used. however, hydrogen-exchanged zeolite decreased surface basicity and increased methane formation.
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    86. 86
      Xu, Q.; He, D.; Fujiwara, M.; Tanaka, M.; Matsumura, Y.; Souma, Y.; Ando, H.; Yamanaka, H. Hydrogenation of Carbon Dioxide over Fe-Cu-Na/Zeolite Composite Catalysts. Stud. Surf. Sci. Catal. 1998, 114, 423– 426,  DOI: 10.1016/S0167-2991(98)80786-6
      Google Scholar
      86
      Hydrogenation of carbon dioxide over Fe-Cu-Na/zeolite composite catalysts
      Xu, Qiang; He, Dehua; Fujiwara, Masahiro; Tanaka, Mutsuo; Matsumura, Yasuyuki; Souma, Yoshie; Ando, Hisanori; Yamanaka, Hiroshi
      Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 423-426CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
      Phys. mixts. of sodium-rich, iron-based catalysts with zeolites greatly improved their activity for carbon dioxide hydrogenation to hydrocarbons at 250°. Sodium migration from the surface of the iron-based catalyst to the zeolite via solid-solid reaction accounts for this change of catalytic activity.
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      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXjt1ajsLs%253D&md5=9d1ceb366992784881b6c16d55e4ab68
    87. 87
      Tan, Y.; Fujiwara, M.; Ando, H.; Xu, Q.; Souma, Y. Selective Formation of iso-Butane from Carbon Dioxide and Hydrogen over Composite Catalysts. Stud. Surf. Sci. Catal. 1998, 114, 435– 438,  DOI: 10.1016/S0167-2991(98)80789-1
      Google Scholar
      87
      Selective formation of iso-butane from carbon dioxide and hydrogen over composite catalysts
      Tan, Yisheng; Fujiwara, Masahiro; Ando, Hisanori; Xu, Qiang; Souma, Yoshie
      Studies in Surface Science and Catalysis (1998), 114 (Advances in Chemical Conversions for Mitigating Carbon Dioxide), 435-438CODEN: SSCTDM; ISSN:0167-2991. (Elsevier Science B.V.)
      The hydrogenation of carbon dioxide over composite catalysts comprised of Fe-Zn-M (M = Cr, Al, Ga, or Zr) and HY zeolite gives isobutane with high selectivities. The mechanism of isobutane formation combines the methanol synthesis reaction and the methanol-to-gasoline reaction, and olefins are important intermediates for isobutane formation. Isobutane can be dehydrogenated to isobutylene for MTBE prodn.
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    88. 88
      Nam, S. S.; Kim, H.; Kishan, G.; Choi, M. J.; Lee, K. W. Catalytic Conversion of Carbon Dioxide into Hydrocarbons over Iron Supported on Alkali Ion-Exchanged Y-Zeolite Catalysts. Appl. Catal., A 1999, 179, 155– 163,  DOI: 10.1016/S0926-860X(98)00322-6
      Google Scholar
      88
      Catalytic conversion of carbon dioxide into hydrocarbons over iron supported on alkali ion-exchanged Y-zeolite catalysts
      Nam, Sang-Sung; Kim, Ho; Kishan, Gurram; Choi, Myoung-Jae; Lee, Kyu-Wan
      Applied Catalysis, A: General (1999), 179 (1-2), 155-163CODEN: ACAGE4; ISSN:0926-860X. (Elsevier Science B.V.)
      Iron supported on HY-zeolite and on alkali metal (Li, Na, K, Rb) ion exchanged Y-zeolite prepd. by impregnation technique have been characterized by XRD, AAS, BET surface area, CO2 chemisorption, temp. programmed redn. (TPR) and temp. programmed decarburization (TPDC) techniques. These catalysts have been tested for catalytic activity for CO2 hydrogenation to hydrocarbons. The XRD patterns of Fe/HY catalysts indicate the formation of Fe2O3 monolayer at 17 wt.% Fe. It is found that alkali metals exchanged in zeolite-Y increase the basicity of the catalyst surface, which influence the activity and selectivity of the catalysts in CO2 hydrogenation. The TPR profile of Fe2O3 catalyst is obsd. to contain only two peaks, corresponding to the redn. of Fe2O3 to Fe0 through Fe3O4. However, the TPR profiles of Fe/MY catalysts contain three peaks, which indicate the formation of iron phase through FeO phase. The peak corresponding to the redn. of Fe3O4 to FeO is obsd. to increase in intensity and in area and to shift to higher temps. in the order: H<Li<Na<K<Rb. The peaks in the TPDC profiles of the catalysts, which represent the redn. of carbide structures, are also obsd. to increase in area and to shift to higher temps. The CO2 conversion and the total hydrocarbon selectivity are found to vary over a narrow range, whereas the selectivities of C2-C4 olefins and C5+ hydrocarbons are very much influenced by the alkali metal present in the catalyst. The activities of the catalysts are correlated with physico-chem. characteristics of the catalysts.
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      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXhsVegurw%253D&md5=00f27dd7162677e90299b7bc7d9cb3c9
    89. 89
      Nam, S. S.; Kishan, G.; Lee, M. W.; Choi, M. J.; Lee, K. W. Selective Synthesis of C2-C4 Olefins and C5+ Hydrocarbons over Unpromoted and Cerium-Promoted Iron Catalysts Supported on Ion Exchanged (H, K) Zeolite-Y. J. Chem. Res., Synop. 1999, 5, 344– 345,  DOI: 10.1039/a900457b
      Google Scholar
      There is no corresponding record for this reference.
    90. 90
      Li, Z.; Wang, J.; Qu, Y.; Liu, H.; Tang, C.; Miao, S.; Feng, Z.; An, H.; Li, C. Highly Selective Conversion of Carbon Dioxide to Lower Olefins. ACS Catal. 2017, 7, 8544– 8548,  DOI: 10.1021/acscatal.7b03251
      Google Scholar
      90
      Highly Selective Conversion of Carbon Dioxide to Lower Olefins
      Li, Zelong; Wang, Jijie; Qu, Yuanzhi; Liu, Hailong; Tang, Chizhou; Miao, Shu; Feng, Zhaochi; An, Hongyu; Li, Can
      ACS Catalysis (2017), 7 (12), 8544-8548CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)
      Conversion of CO2 to value-added chems. has been a long-standing objective, and direct hydrogenation of CO2 to lower olefins is highly desirable but still challenging. Herein, we report a selective conversion of CO2 to lower olefins through CO2 hydrogenation over a ZnZrO/SAPO tandem catalyst fabricated with a ZnO-ZrO2 solid soln. and a Zn-modified SAPO-34 zeolite, which can achieve a selectivity for lower olefins as high as 80-90% among hydrocarbon products. This is realized on the basis of the dual functions of the tandem catalyst: hydrogenation of CO2 on the ZnO-ZrO2 solid soln. and lower olefins prodn. on the SAPO zeolite. The thermodn. and kinetic coupling between the tandem reactions enable the highly efficient conversion of CO2 to lower olefins. Furthermore, this catalyst is stable toward thermal and sulfur treatments, showing potential industrial application.
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