Room-Temperature CO2 Hydrogenation to Methanol over Air-Stable hcp-PdMo Intermetallic CatalystClick to copy article linkArticle link copied!
- Hironobu SugiyamaHironobu SugiyamaMDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Yokohama 226-8503, JapanMore by Hironobu Sugiyama
- Masayoshi MiyazakiMasayoshi MiyazakiMDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Yokohama 226-8503, JapanMore by Masayoshi Miyazaki
- Masato SasaseMasato SasaseMDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Yokohama 226-8503, JapanMore by Masato Sasase
- Masaaki Kitano*Masaaki Kitano*Email for M.K.: [email protected]MDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Yokohama 226-8503, JapanAdvanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, JapanMore by Masaaki Kitano
- Hideo Hosono*Hideo Hosono*Email for H.H.: [email protected]MDX Research Center for Element Strategy, International Research Frontiers Initiative, Tokyo Institute of Technology, Yokohama 226-8503, JapanInternational Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, JapanMore by Hideo Hosono
Abstract
CO2 hydrogenation to methanol is one of the most promising routes to CO2 utilization. However, difficulty in CO2 activation at low temperature, catalyst stability, catalyst preparation, and product separation are obstacles to the realization of a practical hydrogenation process under mild conditions. Here, we report a PdMo intermetallic catalyst for low-temperature CO2 hydrogenation. This catalyst can be synthesized by the facile ammonolysis of an oxide precursor and exhibits excellent stability in air and the reaction atmosphere and significantly enhances the catalytic activity for CO2 hydrogenation to methanol and CO compared with a Pd catalyst. A turnover frequency of 0.15 h–1 was achieved for methanol synthesis at 0.9 MPa and 25 °C, which is comparable to or higher than that of the state-of-the-art heterogeneous catalysts under higher-pressure conditions (4–5 MPa).
This publication is licensed under
License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format and to adapt(remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
Creative Commons (CC): This is a Creative Commons license.
Attribution (BY): Credit must be given to the creator.
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
Climate change and the depletion of fossil fuels are two major problems we have faced in recent years, and thus a reduction of greenhouse gas emissions into the atmosphere and the search for alternative carbon sources for energy and chemicals are urgent issues. (1) The development of conversion processes from CO2, a representative greenhouse gas, to valuable chemicals is a solution to both problems, and thus the exploration of catalysts for CO2 utilization is accelerating worldwide. (2−4) Methanol is one of the most promising conversion targets for CO2 because it can be used as a raw material for various fine chemicals, as a fuel additive, and as an energy carrier. (5,6) Due to similarities with the industrial syngas-to-methanol process, Cu-based and Pd-based catalysts have been investigated under high-temperature and -pressure conditions (generally 200–300 °C and 3–10 MPa) for CO2 hydrogenation to methanol. (7) CO2 hydrogenation to methanol is an exothermic reaction (CO2 + 3H2 → CH3OH + H2O, ΔH298 K = −49.4 kJ mol–1); therefore, a high reaction temperature is thermodynamically unfavorable. The development of catalysts that enable low-temperature operation has thus been vigorously pursued.
Although several success stories of low-temperature methanol synthesis (≤100 °C) over homogeneous catalysts have been reported, (8−10) heterogeneous catalysts are preferable for practical applications over homogeneous catalysts, with respect to product separation, catalyst stability, and the complexity of catalyst preparation. (5,11) These requirements have led to active research on heterogeneous catalysts for low-temperature methanol synthesis in recent years. (12−17) Consequently, heterogeneous catalysts that are active even at room temperature (≤30 °C) have recently begun to be reported. (18,19) There is no doubt that CO2 conversion at room temperature is attractive because it requires no heat source at all; however, the conversion efficiency of these catalysts is extremely low, and therefore much more active catalysts are required for practical use.
Here we report that a PdMo intermetallic, which was prepared via a facile ammonolysis process, works as an efficient and stable catalyst for low-temperature CO2 hydrogenation. The catalytic performance of the PdMo catalyst was significantly improved compared with a Pd catalyst, which resulted in the realization of continuous methanol synthesis at room temperature.
PdMo catalysts were prepared via ammonolysis of the oxide precursor. Figure 1a shows X-ray diffraction (XRD) profiles of the PdMo catalysts with different Pd/Mo ratios. At low Pd content in the precursor, Mo2N was formed as the main phase. As the Pd content increased, another phase with the XRD pattern close to hcp-PdMo intermetallic (Supplementary Note 1) appeared and almost a single phase was obtained at a Pd/Mo ratio of 1.08. HAADF-STEM observations of the single-phase sample (Pd/Mo = 1.08) revealed an ordered structure with alternating layers of Pd and Mo, which suggests that the obtained sample is an intermetallic compound (Figure 1b and Figure S2). The results of compositional analysis of the unknown phase using the single-phase sample are summarized in Table S1. Electron probe microanalysis (EPMA) revealed that the unknown phase consists of Pd (58.1 ± 3.1 wt %), Mo (39.2 ± 3.3 wt %), N (1.1 ± 0.4 wt %), and O (1.6 ± 0.6 wt %). For Pd and Mo, a similar composition (Pd = 51.3 wt % and Mo = 44.5 wt %) was confirmed for the solution of this phase by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Energy dispersive X-ray spectroscopy (EDX) mapping of a single particle showed that Pd and Mo were homogeneously distributed (Figure 1c). The amount of anions (N ≈ 2.0 wt % and O = 1.8 wt %) was also estimated by temperature-programmed desorption (TPD) measurements (Figure 1d and Figure S3), and CHN elemental combustion analysis. From these results, the elemental composition of the unknown phase was estimated to be Pd0.6Mo0.4N0.1O0.1. Based on these results, the unknown phase was tentatively identified as h-PdMo. After TPD measurement, this phase was decomposed to Pd and Mo (Figure S4), which suggests that incorporated nitrogen contributes to the stabilization of this phase. This instability is in agreement with the metastability of h-PdMo in the Pd–Mo system. Below the nitrogen desorption temperature (ca. 400 °C), this phase is thermally and chemically stable and therefore is not decomposed, even when handled in air for a long period of time (Figure 1e). Such robustness is very important when considering the practicality of a catalyst.
h-PdMo/Mo2N (Pd/Mo = 0.05) was next investigated as a catalyst for CO2 hydrogenation in comparison with Pd nanoparticles supported on Mo2N (Pd/Mo2N) (Figure S5). According to the ICP-AES analysis, the actual amounts of Pd (4.4 and 4.6 wt %) in these two catalysts were comparable (Table S2). To confirm the state of Pd on both catalysts, microstructural observation and compositional mapping were conducted using scanning transmission electron microscopy (STEM) with EDX (Figure 2). The STEM images showed that nanoparticles were loaded on the support in both catalysts (Figure 2a,f). The distribution of Pd in h-PdMo/Mo2N overlapped with the regions of strong Mo and N intensity (Figure 2b–d), which indicates the formation of h-PdMo intermetallic nanoparticles attached onto Mo2N (Figure 2e). On the other hand, Pd in Pd/Mo2N was distributed separately from Mo and N (Figure 2g–i), which indicates that nanoparticles consisting of only Pd were loaded onto Mo2N (Figure 2j). Fast Fourier transform (FFT) pattern analyses for each nanoparticle further supported these results (Figures S6 and S7).
Figure 3a compares the methanol synthesis activity for CO2 hydrogenation over the h-PdMo/Mo2N and Pd/Mo2N catalysts at ambient pressure. The catalytic activity of h-PdMo/Mo2N was significantly enhanced and methanol was thus produced even at low temperatures below 100 °C, whereas Pd/Mo2N showed some activity at elevated temperatures but no measurable activity at such low temperatures. The catalytic performance of the h-PdMo/Mo2N catalyst is reproducible, with a standard deviation below ±3 μmol g–1 h–1 (Figure S8). No methanol production was observed from temperature-programmed reaction of H2 (H2-TPR) on the h-PdMo/Mo2N catalyst (Figure S9). The h- PdMo/Mo2N (Pd/Mo = 0.05) catalyst synthesized by using Pd(NH3)4Cl2·H2O as the Pd source also showed catalytic activity similar to that derived from Pd(CH3COO)2 (Figure S10). These results confirmed that the methanol production was not due to hydrogenation of organic residues (e.g., Pd(CH3COO)2) but due to the catalytic reaction. Mo2N alone showed negligible catalytic activity, and h-PdMo showed activity similar to that of h-PdMo/Mo2N (Figure S11a,b); therefore, Mo2N itself works as a support to disperse h-PdMo nanoparticles, and the number of active sites exposed on the surface of h-PdMo is comparable to that on h-PdMo/Mo2N. The Cu/ZnO/Al2O3 catalyst, one of the benchmark catalysts for CO2 hydrogenation to methanol, also shows low activity under such low-temperature conditions, despite containing more active metal (Cu = 58.1 wt %) than h-PdMo/Mo2N (Pd = 4.4 wt %) (Figure S12). The apparent activation energy for h-PdMo/Mo2N was 27 kJ mol–1, which is less than half that for Pd/Mo2N (78 kJ mol–1) (Figure 3b) and the lowest among the other Pd-based catalysts reported to date (37–84 kJ mol–1) (Table S3). To confirm the effect of diffusion resistance on the catalytic activity, methanol synthesis activity was investigated at different flow rates when W/F (catalyst weight/flow rate) is fixed at a constant value. As shown in Figure S13, methanol synthesis rates are constant regardless of the flow rate, indicating that the reaction on h-PdMo/Mo2N catalyst is in kinetic control rather than diffusion control. The stability of the catalyst was also examined by a long-term continuous reaction test. Even under the low-temperature condition, the h-PdMo/Mo2N catalyst produced methanol continuously without degradation over 100 h at 100 °C (Figure 3c), and there was no significant change in the crystal structure before and after the reaction (Figure 3d), which indicates that h-PdMo/Mo2N is a stable catalyst under CO2 hydrogenation conditions. Similar results were obtained for the h-PdMo catalyst (Figure S11c,d).
From a chemical equilibrium perspective, CO2 hydrogenation to methanol is more favorable under higher-pressure conditions. (5) Therefore, the catalytic performance over h-PdMo/Mo2N catalyst was also investigated under pressurized conditions up to 0.9 MPa with the aim of increasing the catalytic activity. Methanol synthesis activity over the h-PdMo catalyst was consequently improved with an increase of the reaction pressure (Figure S14). Figure 4a shows the temperature dependence of catalytic activity at 0.9 MPa. It should be noted that methanol was produced, even at room temperature (25 °C). The formation of isotope-labeled methanol (13CH3OH, m/z = 33) from 13CO2 and H2 was also confirmed under similar reaction conditions (Figure S15). h-PdMo alone (single-phase PdMo) also showed catalytic activity similar to that of h-PdMo/Mo2N, and their apparent activation energies were in the range of 26–28 kJ mol–1, regardless of the different pressure conditions (Figure 4a and Figure S16). These results suggest that h-PdMo effectively activates CO2 to produce methanol at low temperatures under pressurized conditions. The long-term continuous reaction test revealed that methanol was produced catalytically, even at room temperature (Figure 4b), without degradation of the h-PdMo phase (Figure S17). Assuming that all the metals on the surface of the h-PdMo catalyst are active sites, the turnover frequency (TOF) of h-PdMo was estimated to be 0.15 h–1 (0.9 MPa, 25 °C), although the actual number of active sites is less than that, and thus the calculated TOF value should be an underestimate. To obtain further insight into the CO2 activation and hydrogenation over h-PdMo/Mo2N at room temperature, observation of reaction intermediates in CO2 hydrogenation was performed by in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements (Figure 4c). When the reaction gas (CO2:H2 = 1:3) was introduced, CO* and CH3O* species (* represents surface adsorbates) were observed as reaction intermediates. The infrared peaks at 2057 and 2076 cm–1 are assigned to linearly absorbed CO* species, and the peaks at 1051, 2852, and 2925 cm–1 are assigned to a C–O stretching vibration ν(CO) and C–H symmetric and asymmetric stretching vibrations ν(CH) of CH3O* species, respectively. (19−21) The peak positions of the adsorbed species on the h-PdMo/Mo2N catalyst were close to those on Mo site of the reduced MoS2 catalyst (CO*, 2078 cm–1; ν(CH) of CH3O*, 2846 and 2915 cm–1) (19) rather than those on Pd metal surface (CO*(linear): 2083–2091 cm–1, ν(CH) of CH3O*: 2860 and 2960 cm–1). (21−23) In addition, CO-TPD indicates that CO is more strongly adsorbed on h-PdMo than on Pd (Figure S18). Therefore, CO* and CH3O* species are considered to be adsorbed on the Mo site rather than Pd site. These characteristic peaks of CH3O* were also observed over h-PdMo alone, and the peak intensities increased with the temperature (Figure S19), which indicates that CH3O* is an intermediate in CO2 hydrogenation to methanol over h-PdMo catalysts. The time course of intermediate formation implies that the decomposition of CO2 to CO* occurs first, and CO* is subsequently hydrogenated to form CH3O*. These results clearly demonstrate that CO2 activation and hydrogenation proceed over the h-PdMo catalysts, even under ambient-pressure and room-temperature conditions.
There are two major reaction pathways for CO2 hydrogenation to methanol: (I) formate pathway and (II) reverse water-gas shift (RWGS: CO2 + H2 → CO + H2O) and subsequent CO hydrogenation pathway (R&C pathway). (24−26) The DRIFT spectroscopy results (Figure 4c) indicate that CO2 hydrogenation to methanol over h-PdMo appears to proceed via the R&C pathway. Indeed, h-PdMo/Mo2N catalyst also enhanced methanol synthesis from CO and H2, and the apparent activation energies for CO and CO2 hydrogenation to methanol over h-PdMo/Mo2N catalyst were very close, which is generally observed in Pd-based catalysts because the R&C pathway is energetically favorable (Figure 3b and Figure S20). (26) The Pd/Mo2N catalyst showed a similar tendency. These results strongly suggest that CO2 hydrogenation to methanol on the h-PdMo/Mo2N catalyst proceeds via the R&C pathway. The comparable activation energies for CO and CO2 hydrogenation on the h-PdMo/Mo2N catalyst suggest that the CO hydrogenation process is rate-determining for CO2 hydrogenation to methanol. The rate-determining step for CO hydrogenation to methanol on the Pd catalyst is known to be the HCO formation step (CO + H → HCO). (27) As shown in Figure 4c, the CO peak for h-PdMo/Mo2N catalyst is red-shifted as compared to that for conventional Pd catalysts. (21−23) Therefore, the adsorbed CO on the h-PdMo/Mo2N catalyst is more activated than on Pd, which is favorable for promotion of HCO formation. (28) The difference in activation energy between the h-PdMo/Mo2N and Pd/Mo2N catalysts can be attributed to the promotion of HCO formation on the h-PdMo/Mo2N catalyst.
On the h-PdMo/Mo2N, noticeable CO production was observed at temperatures above 100 °C (Figure S21a). CH4 formation was also observed at temperatures above 140 °C (Figure S21b), which suggests that hydrogenation proceeds more readily than on Pd/Mo2N. Selectivity of methanol over the h-PdMo/Mo2N catalyst decreased with increasing reaction temperature but was clearly higher than that over the Pd/Mo2N catalyst at temperatures below 140 °C (Figure S21c,d). Given that the hydrogenation of CO to HCO is the rate-determining step, it is difficult to suppress the CO production in the R&C pathway. However, the methanol selectivity would be much improved by enhancing the CO adsorption and low-temperature hydrogenation capability of the h-PdMo catalyst.
Finally, the catalytic activity of the h-PdMo catalyst was compared with those of previously reported room-temperature methanol synthesis catalysts. (18,19) Figure 5 summarizes the TOFs for CO2 hydrogenation to methanol over the h-PdMo catalyst under various reaction conditions, along with those of the reported catalysts. Comparing the catalytic performance of these catalysts at room temperature, the activity of the h-PdMo catalyst was 1 order of magnitude higher than that of the Ir complex catalyst (at 4 MPa) and comparable to that of the few-layered MoS2 (FL-MoS2) catalyst (at 5 MPa), despite the reaction pressure of <1 MPa. Furthermore, when compared under the same reaction condition (ca. 1 MPa, 60 °C), the TOF of the h-PdMo catalyst was more than 50 times higher than that of the Ir complex catalyst. In addition, the TOF value of 0.15 h–1 for the h-PdMo catalyst (0.9 MPa, 25 °C) is comparable to the TOF values of 0.05–0.33 h–1 for Cu- and Pd-based catalysts under harsh conditions (2–7 MPa, 100–250 °C) (Table S4). It should be noted that the activity of the h-PdMo catalyst increased at higher pressure, as shown in Figure S14, so that even higher activity could be expected under reaction conditions above 1 MPa.
In summary, we have created a highly active and stable PdMo intermetallic catalyst, h-PdMo, and achieved room-temperature methanol synthesis from CO2 and H2. The h-PdMo catalyst can be prepared via the facile ammonolysis of an oxide precursor, and the catalyst exhibits long-term stability in air. These features are favorable for the practical use of the catalyst. For low-temperature CO2 hydrogenation to methanol, the h-PdMo/Mo2N catalyst had significantly enhanced catalytic activity and much lower activation energy than the Pd/Mo2N catalyst. The methanol synthesis activity of the h-PdMo catalysts was further improved by pressurization, which resulted in continuous CO2 hydrogenation to methanol at room temperature. The h-PdMo catalyst had a TOF of 0.15 h–1 at 0.9 MPa and 25 °C, which is comparable to or higher than that of the state-of-the-art catalysts under higher-pressure conditions (4–5 MPa). The h-PdMo catalyst also promotes the RWGS reaction above 100 °C. These results indicate that h-PdMo catalysts are more effective for CO2 activation and hydrogenation at low temperatures than the Pd catalyst. Controlling the selectivity of products remains a challenge at the next stage. Furthermore, the CO2 conversion under the tested conditions (∼1% even at 180 °C) is still far too low compared to the thermodynamic equilibrium value (ca. 10%) (29) (Table S5). However, the catalytic performance could be much improved by tuning the catalyst structure (e.g., higher surface area, loading on supports other than Mo2N, addition of a third metal) and catalytic process. This discovery provides a frontier for catalyst development, not only for low-temperature methanol synthesis and CO2 conversion reactions but also for other reactions catalyzed by Pd.
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.2c13801.
XRD patterns for the Pd–Mo catalyst and the previously reported PdMo intermetallic, FFT of a single h-PdMo particle, N2-TPD profiles for h-PdMo and Mo2N, XRD patterns for the h-PdMo catalyst before and after TPD measurements, XRD patterns for the h-PdMo/Mo2N and Pd/Mo2N catalysts, high-resolution TEM images of h-PdMo/Mo2N and Pd/Mo2N, FFT of a single h-PdMo nanoparticle and Pd nanoparticle on Mo2N, reproducibility test of h-PdMo/Mo2N catalyst, H2-TPR profile for the h-PdMo/Mo2N catalyst, XRD patterns and methanol synthesis activity of h-PdMo/Mo2N catalyst synthesized by using Pd(NH3)4Cl2·H2O as a Pd source, catalytic activity over Mo2N and h-PdMo catalysts under ambient pressure, comparison of catalytic activity over h-PdMo/Mo2N and Cu/ZnO/Al2O3 catalysts, CO2 hydrogenation with different flow rates, pressure dependence of catalytic activity over the h-PdMo catalyst, GC-MS spectrum of 13CH3OH obtained from 13CO2, catalytic activity and activation energy over the h-PdMo/Mo2N and h-PdMo catalysts under pressurized conditions, XRD patterns for the h-PdMo catalyst before and after methanol synthesis, CO-TPD profiles for h-PdMo and Pd, DRIFT spectra over the h-PdMo catalyst, CO hydrogenation to methanol over the h-PdMo/Mo2N catalyst under atmospheric pressure, synthesis rate of byproducts and product distribution during CO2 hydrogenation, and tables for compositional analysis, structural properties of the studied catalysts, activation energies over various Pd-based catalysts, comparison of TOFs over different catalysts, and CO2 conversion over the h-PdMo/Mo2N catalyst (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.
Acknowledgments
This work was supported by the FOREST Program (no. JPMJFR203A) from the Japan Science and Technology Agency (JST) and Kakenhi Grants-in-Aid (no. JP22H00272) from the Japan Society for the Promotion of Science (JSPS). H.S. was supported by JSPS KAKENHI (grant no. JP21J14346). The authors thank the Materials Analysis Division, Open Facility Center, Tokyo Institute of Technology, for ICP and CHN elemental analysis.
References
This article references 29 other publications.
- 1Höök, M.; Tang, X. Depletion of Fossil Fuels and Anthropogenic Climate Change─A Review. Energy Policy 2013, 52, 797– 809, DOI: 10.1016/j.enpol.2012.10.046Google ScholarThere is no corresponding record for this reference.
- 2Artz, J.; Müller, T. E.; Thenert, K.; Kleinekorte, J.; Meys, R.; Sternberg, A.; Bardow, A.; Leitner, W. Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment. Chem. Rev. 2018, 118 (2), 434– 504, DOI: 10.1021/acs.chemrev.7b00435Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFemsrbL&md5=5348e984489e8e3e18368ed6a9088ec1Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle AssessmentArtz, Jens; Mueller, Thomas E.; Thenert, Katharina; Kleinekorte, Johanna; Meys, Raoul; Sternberg, Andre; Bardow, Andre; Leitner, WalterChemical Reviews (Washington, DC, United States) (2018), 118 (2), 434-504CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chems. and even to specialty products with biol. activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined anal. of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochem. value chain. This anal. and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem "CO2 emissions" from todays' industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future prodn. Thus, the motivation to develop CO2-based chem. does not depend primarily on the abs. amt. of CO2 emissions that can be remediated by a single technol. Rather, CO2-based chem. is stimulated by the significance of the relative improvement in carbon balance and other crit. factors defining the environmental impact of chem. prodn. in all relevant sectors in accord with the principles of green chem.
- 3Gao, P.; Li, S.; Bu, X.; Dang, S.; Liu, Z.; Wang, H.; Zhong, L.; Qiu, M.; Yang, C.; Cai, J.; Wei, W.; Sun, Y. Direct Conversion of CO2 into Liquid Fuels with High Selectivity over a Bifunctional Catalyst. Nature Chem. 2017, 9 (10), 1019– 1024, DOI: 10.1038/nchem.2794Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVSjt7bI&md5=4ef37e087edf5dfbaf26bcd93105f584Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalystGao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, YuhanNature Chemistry (2017), 9 (10), 1019-1024CODEN: NCAHBB; ISSN:1755-4330. (Nature Research)Although considerable progress was made in CO2 hydrogenation to various C1 chems., it is still a great challenge to synthesize value-added products with ≥2 carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here the authors present a bifunctional catalyst composed of reducible In oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The O vacancies on the In2O3 surfaces activate CO2 and H to form MeOH, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane no. The proximity of these 2 components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Also, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.
- 4Kim, D.-Y.; Ham, H.; Chen, X.; Liu, S.; Xu, H.; Lu, B.; Furukawa, S.; Kim, H.-H.; Takakusagi, S.; Sasaki, K.; Nozaki, T. Cooperative Catalysis of Vibrationally Excited CO2 and Alloy Catalyst Breaks the Thermodynamic Equilibrium Limitation. J. Am. Chem. Soc. 2022, 144 (31), 14140– 14149, DOI: 10.1021/jacs.2c03764Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhvFWhsrrK&md5=3f49b0d802c776e8e9a81cd2a65526e2Cooperative Catalysis of Vibrationally Excited CO2 and Alloy Catalyst Breaks the Thermodynamic Equilibrium LimitationKim, Dae-Yeong; Ham, Hyungwon; Chen, Xiaozhong; Liu, Shuai; Xu, Haoran; Lu, Bang; Furukawa, Shinya; Kim, Hyun-Ha; Takakusagi, Satoru; Sasaki, Koichi; Nozaki, TomohiroJournal of the American Chemical Society (2022), 144 (31), 14140-14149CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Using nonthermal plasma (NTP) to promote CO2 hydrogenation is one of the most promising approaches that overcome the limitations of conventional thermal catalysis. However, the catalytic surface reaction dynamics of NTP-activated species are still under debate. The NTP-activated CO2 hydrogenation was investigated in Pd2Ga/SiO2 alloy catalysts and compared to thermal conditions. Although both thermal and NTP conditions showed close to 100% CO selectivity, it is worth emphasizing that when activated by NTP, CO2 conversion not only improves more than 2-fold under thermal conditions but also breaks the thermodn. equil. limitation. Mechanistic insights into NTP-activated species and alloy catalyst surface were investigated by using in situ transmission IR spectroscopy, where catalyst surface species were identified during NTP irradn. Moreover, in in situ X-ray absorption fine-structure anal. under reaction conditions, the catalyst under NTP conditions not only did not undergo restructuring affecting CO2 hydrogenation but also could clearly rule out catalyst activation by heating. In situ characterizations of the catalysts during CO2 hydrogenation depict that vibrationally excited CO2 significantly enhances the catalytic reaction. The agreement of approaches combining exptl. studies and d. functional theory (DFT) calcns. substantiates that vibrationally excited CO2 reacts directly with hydrogen adsorbed on Pd sites while accelerating formate formation due to neighboring Ga sites. Moreover, DFT anal. deduces the key reaction pathway that the decompn. of monodentate formate is promoted by plasma-activated hydrogen species. This work enables the high designability of CO2 hydrogenation catalysts toward value-added chems. based on the electrification of chem. processes via NTP.
- 5Zhong, J.; Yang, X.; Wu, Z.; Liang, B.; Huang, Y.; Zhang, T. State of the Art and Perspectives in Heterogeneous Catalysis of CO2 Hydrogenation to Methanol. Chem. Soc. Rev. 2020, 49 (5), 1385– 1413, DOI: 10.1039/C9CS00614AGoogle Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksFens7w%253D&md5=78445dfba315564c750d268dd2296f70State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanolZhong, Jiawei; Yang, Xiaofeng; Wu, Zhilian; Liang, Binglian; Huang, Yanqiang; Zhang, TaoChemical Society Reviews (2020), 49 (5), 1385-1413CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. The ever-increasing amt. of anthropogenic carbon dioxide (CO2) emissions has resulted in great environmental impacts. The selective hydrogenation of CO2 to methanol, the first target in the liq. sunshine vision, not only effectively mitigates the CO2 emissions, but also produces value-added chems. and fuels. This crit. review provides a comprehensive view of the significant advances in heterogeneous catalysis for methanol synthesis through direct hydrogenation of CO2. The challenges in thermodn. are addressed first. Then the progress in conventional Cu-based catalysts is discussed in detail, with an emphasis on the structural, chem., and electronic promotions of supports and promoters, the prepn. methods and precursors of Cu-based catalysts, as well as the proposed models for active sites. We also provide an overview of the progress in noble metal-based catalysts, bimetallic catalysts including alloys and intermetallic compds., as well as hybrid oxides and other novel catalytic systems. The developments in mechanistic aspects, reaction conditions and optimization, as well as reactor designs and innovations are also included. The advances in industrial applications for methanol synthesis are further highlighted. Finally, a summary and outlook are provided.
- 6Martin, O.; Martín, A. J.; Mondelli, C.; Mitchell, S.; Segawa, T. F.; Hauert, R.; Drouilly, C.; Curulla-Ferré, D.; Pérez-Ramírez, J. Indium Oxide as a Superior Catalyst for Methanol Synthesis by CO2 Hydrogenation. Angew. Chem., Int. Ed. 2016, 55 (21), 6261– 6265, DOI: 10.1002/anie.201600943Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xks1elurs%253D&md5=a6c662dc8dd8bd688ee5e3386221229aIndium Oxide as a Superior Catalyst for Methanol Synthesis by CO2 HydrogenationMartin, Oliver; Martin, Antonio J.; Mondelli, Cecilia; Mitchell, Sharon; Segawa, Takuya F.; Hauert, Roland; Drouilly, Charlotte; Curulla-Ferre, Daniel; Perez-Ramirez, JavierAngewandte Chemie, International Edition (2016), 55 (21), 6261-6265CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)MeOH synthesis by CO2 hydrogenation is attractive in view of avoiding the environmental implications assocd. with the prodn. of the traditional syngas feedstock and mitigating global warming. However, there still is a lack of efficient catalysts for such alternative processes. Herein, the authors unveil the high activity, 100% selectivity, and remarkable stability for 1000 h on stream of In2O3 supported on ZrO2 under industrially relevant conditions. This strongly contrasts to the benchmark Cu-ZnO-Al2O3 catalyst, which is unselective and experiences rapid deactivation. In-depth characterization of the In2O3-based materials points towards a mechanism rooted in the creation and annihilation of O vacancies as active sites, whose amt. can be modulated in situ by co-feeding CO and boosted through electronic interactions with the zirconia carrier. These results constitute a promising basis for the design of a prospective technol. for sustainable MeOH prodn.
- 7Jiang, X.; Nie, X.; Guo, X.; Song, C.; Chen, J. G. Recent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous Catalysis. Chem. Rev. 2020, 120 (15), 7984– 8034, DOI: 10.1021/acs.chemrev.9b00723Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXis1Whtr8%253D&md5=65a804dac18033b954e193f3354ecfbfRecent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous CatalysisJiang, Xiao; Nie, Xiaowa; Guo, Xinwen; Song, Chunshan; Chen, Jingguang G.Chemical Reviews (Washington, DC, United States) (2020), 120 (15), 7984-8034CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The utilization of fossil fuels has enabled an unprecedented era of prosperity and advancement of well-being for human society. However, the assocd. increase in anthropogenic carbon dioxide (CO2) emissions can neg. affect global temps. and ocean acidity. Moreover, fossil fuels are a limited resource and their depletion will ultimately force one to seek alternative carbon sources to maintain a sustainable economy. Converting CO2 into value-added chems. and fuels, using renewable energy, is one of the promising approaches in this regard. Major advances in energy-efficient CO2 conversion can potentially alleviate CO2 emissions, reduce the dependence on nonrenewable resources, and minimize the environmental impacts from the portions of fossil fuels displaced. Methanol (CH3OH) is an important chem. feedstock and can be used as a fuel for internal combustion engines and fuel cells, as well as a platform mol. for the prodn. of chems. and fuels. As one of the promising approaches, thermocatalytic CO2 hydrogenation to CH3OH via heterogeneous catalysis has attracted great attention in the past decades. Major progress has been made in the development of various catalysts including metals, metal oxides, and intermetallic compds. In addn., efforts are also put forth to define catalyst structures in nanoscale by taking advantage of nanostructured materials, which enables the tuning of the catalyst compn. and modulation of surface structures and potentially endows more promising catalytic performance in comparison to the bulk materials prepd. by traditional methods. Despite these achievements, significant challenges still exist in developing robust catalysts with good catalytic performance and long-term stability. In this review, a comprehensive overview is provided of the recent advances in this area, esp. focusing on structure-activity relationship, as well as the importance of combining catalytic measurements, in situ characterization, and theor. studies in understanding reaction mechanisms and identifying key descriptors for designing improved catalysts.
- 8Schneidewind, J.; Adam, R.; Baumann, W.; Jackstell, R.; Beller, M. Low-Temperature Hydrogenation of Carbon Dioxide to Methanol with a Homogeneous Cobalt Catalyst. Angew. Chem., Int. Ed. 2017, 56 (7), 1890– 1893, DOI: 10.1002/anie.201609077Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsFWjtw%253D%253D&md5=bbce4fd6ca35545589b0dfda3de8369dLow-Temperature Hydrogenation of Carbon Dioxide to Methanol with a Homogeneous Cobalt CatalystSchneidewind, Jacob; Adam, Rosa; Baumann, Wolfgang; Jackstell, Ralf; Beller, MatthiasAngewandte Chemie, International Edition (2017), 56 (7), 1890-1893CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)We describe the 1st homogeneous non-noble metal catalyst for the hydrogenation of CO2 to methanol. The catalyst is formed in situ from [Co(acac)3], Triphos, and HNTf2 and enables the reaction to be performed at 100° without a decrease in activity. Kinetic studies suggest an inner-sphere mechanism, and in situ NMR and MS expts. reveal the formation of the active catalyst through slow removal of the acetylacetonate ligands.
- 9Ribeiro, A. P. C.; Martins, L. M. D. R. S.; Pombeiro, A. J. L. Carbon Dioxide-to-Methanol Single-Pot Conversion Using a C-Scorpionate Iron(II) Catalyst. Green Chem. 2017, 19 (20), 4811– 4815, DOI: 10.1039/C7GC01993AGoogle Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVGjurfP&md5=2cfbba29e0550784e3324ef2e0714ccaCarbon dioxide-to-methanol single-pot conversion using a C-scorpionate iron(II) catalystRibeiro, A. P. C.; Martins, L. M. D. R. S.; Pombeiro, A. J. L.Green Chemistry (2017), 19 (20), 4811-4815CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)The highly efficient eco-friendly synthesis of methanol (44% yield, TONs up to 2.3 × 103) directly from carbon dioxide is achieved by using H2 and the iron(II) scorpionate catalyst [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) in a solvent- or amine-free mild new protocol.
- 10Everett, M.; Wass, D. F. Highly Productive CO2 Hydrogenation to Methanol – a Tandem Catalytic Approach via Amide Intermediates. Chem. Commun. 2017, 53 (68), 9502– 9504, DOI: 10.1039/C7CC04613HGoogle Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVKiu7fJ&md5=645d9f5f54217fc6cd53e4a0f65a8dd1Highly productive CO2 hydrogenation to methanol - a tandem catalytic approach via amide intermediatesEverett, M.; Wass, D. F.Chemical Communications (Cambridge, United Kingdom) (2017), 53 (68), 9502-9504CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A new system for CO2 redn. to methanol has been demonstrated using homogeneous ruthenium catalysts with a range of amine auxiliaries. Modification of this amine has a profound effect on the yield and selectivity of the reaction. A TON of 8900 and TOF of 4500 h-1 is achieved using a [RuCl2(Ph2PCH2CH2NHMe)2] catalyst with a diisopropylamine auxiliary.
- 11Poovan, F.; Chandrashekhar, V. G.; Natte, K.; Jagadeesh, R. V. Synergy between Homogeneous and Heterogeneous Catalysis. Catalysis Science & Technology 2022, 12 (22), 6623– 6649, DOI: 10.1039/D2CY00232AGoogle Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xhs12rsLzK&md5=4874fd881a22aa7d994562ee529c4ac3Synergy between homogeneous and heterogeneous catalysisPoovan, Fairoosa; Chandrashekhar, Vishwas G.; Natte, Kishore; Jagadeesh, Rajenahally V.Catalysis Science & Technology (2022), 12 (22), 6623-6649CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)A review. Catalysis plays a decisive role in the advancement of sustainable processes in chem., pharmaceutical, and agrochem. industries as well as petrochem., material, and energy technologies. Notably, more than 80% of all chem. products involve catalysis processes in at least one stage in their manuf. Thus, for the modernization of chem. synthesis, the applicability of catalysts is crucial. Since the beginning of catalysis, a large no. of both homogeneous and heterogeneous catalysts have been developed and applied for all kinds of synthetic reactions. Among these, homogeneous complexes are active and selective but not stable and they are difficult to recycle or reuse. On the other hand, heterogeneous materials are quite stable and conveniently recyclable, but they exhibit lower activity and selectivity. In catalysis, the development of 'ideal' catalysts, which should be more active and selective as well as stable and easily recyclable, is of prime importance to produce all kinds of chems. including life science mols. In order to develop such catalyst systems, combining both homogeneous and heterogeneous catalysis concepts is considered to be a promising strategy. Applying this approach, special kinds of catalysts such as nanoparticles and single atoms as well as supported homogeneous complexes can be designed. These types of catalysts can overcome the limitations of both molecularly defined complexes and traditional heterogeneous materials. In this respect, in recent years more focus has been paid to the design of these classes of catalysts for org. synthesis. Consequently, in this review, we discuss the application of synergies between homogeneous and heterogeneous catalysis concepts in developing suitable catalysts that exhibit both activity and selectivity as well as stability and reusability. More specifically, selected examples and key achievements made on the prepn. and applications of nanoparticles, single atoms, and supported homogeneous complexes for org. transformations are summarized and discussed.
- 12Ting, K. W.; Toyao, T.; Siddiki, S. M. A. H.; Shimizu, K. Low-Temperature Hydrogenation of CO2 to Methanol over Heterogeneous TiO2-Supported Re Catalysts. ACS Catal. 2019, 9 (4), 3685– 3693, DOI: 10.1021/acscatal.8b04821Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkvVSnu7o%253D&md5=b938d14735a3a7be5958e67842a655afLow-Temperature Hydrogenation of CO2 to Methanol over Heterogeneous TiO2-Supported Re CatalystsTing, Kah Wei; Toyao, Takashi; Siddiki, S. M. A. Hakim; Shimizu, Ken-ichiACS Catalysis (2019), 9 (4), 3685-3693CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)Hydrogenation of carbon dioxide (CO2) to methanol (MeOH) is an effective strategy for CO2 utilization. Because of a low equil. conversion of CO2 to MeOH at high temp., development of efficient catalytic CO2 hydrogenation processes that operate under low reaction temp. is of extreme importance. Herein, we report that TiO2-supported Re (Re(1)/TiO2; Re = 1 wt. %) promotes the selective hydrogenation of CO2 to MeOH (total TON based on Re = 44, MeOH selectivity = 82%) under mild conditions (pCO2 = 1 MPa; pH2 = 5 MPa; T = 150°). Both in terms of TON and methanol selectivity, the performance of Re(1)/TiO2 is superior to that of TiO2 catalysts loaded with other metals and to Re catalysts on other support materials. In addn., our investigations include the reaction mechanism and structure-activity relation for the catalytic system used in this study, suggesting that relatively reduced Re species (oxidn. state: 0-4) of subnanometer size serve as the catalytically active site for the formation of MeOH.
- 13Chen, Y.; Choi, S.; Thompson, L. T. Low Temperature CO2 Hydrogenation to Alcohols and Hydrocarbons over Mo2C Supported Metal Catalysts. J. Catal. 2016, 343, 147– 156, DOI: 10.1016/j.jcat.2016.01.016Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitlChtrg%253D&md5=c0563197ea7a61c1a1ea6e1542c30b3bLow temperature CO2 hydrogenation to alcohols and hydrocarbons over Mo2C supported metal catalystsChen, Yuan; Choi, Saemin; Thompson, Levi T.Journal of Catalysis (2016), 343 (), 147-156CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)A series of M/Mo2C (M = Cu, Pd, Co and Fe) were synthesized and evaluated for CO2 hydrogenation at 135-200 °C in liq. 1,4-dioxane solvent. The Mo2C served as both a support and a co-catalyst for CO2 hydrogenation, exhibiting turnover frequencies of 0.6 × 10-4 and 20 × 10-4 s-1 at 135 and 200 °C, resp. Methanol was the major product at 135 °C, while CH3OH, C2H5OH, and C2+ hydrocarbons were produced at 200 °C. The addn. of Cu and Pd onto the high surface area Mo2C enhanced the prodn. of CH3OH, while Co and Fe enhanced the prodn. of C2+ hydrocarbons. Results for CO2, CO, and CH3OH hydrogenation expts. suggested that CO2 was the primary source for CH3OH while CO was the intermediate to hydrocarbons during CO2 hydrogenation. Characterization of the spent M/Mo2C catalysts revealed very little change in the surface and bulk chemistries and structures, indicating their stability in the liq. environment.
- 14Khan, M. U.; Wang, L.; Liu, Z.; Gao, Z.; Wang, S.; Li, H.; Zhang, W.; Wang, M.; Wang, Z.; Ma, C.; Zeng, J. Pt3Co Octapods as Superior Catalysts of CO2 Hydrogenation. Angew. Chem., Int. Ed. 2016, 55 (33), 9548– 9552, DOI: 10.1002/anie.201602512Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28bltFOjtg%253D%253D&md5=ae35237b5fe4a1b3d00f8cde40576257Pt3 Co Octapods as Superior Catalysts of CO2 HydrogenationKhan Munir Ullah; Wang Liangbing; Liu Zhao; Gao Zehua; Wang Shenpeng; Li Hongliang; Zhang Wenbo; Wang Menglin; Wang Zhengfei; Ma Chao; Zeng JieAngewandte Chemie (International ed. in English) (2016), 55 (33), 9548-52 ISSN:.As the electron transfer to CO2 is a critical step in the activation of CO2 , it is of significant importance to engineer the electronic properties of CO2 hydrogenation catalysts to enhance their activity. Herein, we prepared Pt3 Co nanocrystals with improved catalytic performance towards CO2 hydrogenation to methanol. Pt3 Co octapods, Pt3 Co nanocubes, Pt octapods, and Pt nanocubes were tested, and the Pt3 Co octapods achieved the best catalytic activity. Both the presence of multiple sharp tips and charge transfer between Pt and Co enabled the accumulation of negative charges on the Pt atoms in the vertices of the Pt3 Co octapods. Moreover, infrared reflection absorption spectroscopy confirmed that the high negative charge density at the Pt atoms in the vertices of the Pt3 Co octapods promotes the activation of CO2 and accordingly enhances the catalytic activity.
- 15Bai, S.; Shao, Q.; Feng, Y.; Bu, L.; Huang, X. Highly Efficient Carbon Dioxide Hydrogenation to Methanol Catalyzed by Zigzag Platinum–Cobalt Nanowires. Small 2017, 13 (22), 1604311, DOI: 10.1002/smll.201604311Google ScholarThere is no corresponding record for this reference.
- 16Zheng, X.; Lin, Y.; Pan, H.; Wu, L.; Zhang, W.; Cao, L.; Zhang, J.; Zheng, L.; Yao, T. Grain Boundaries Modulating Active Sites in RhCo Porous Nanospheres for Efficient CO2 Hydrogenation. Nano Res. 2018, 11 (5), 2357– 2365, DOI: 10.1007/s12274-017-1841-7Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFOlsb3I&md5=e506b96b97f40aa4368ed868ed40dcddGrain boundaries modulating active sites in RhCo porous nanospheres for efficient CO2 hydrogenationZheng, Xusheng; Lin, Yue; Pan, Haibin; Wu, Lihui; Zhang, Wei; Cao, Linlin; Zhang, Jing; Zheng, Lirong; Yao, TaoNano Research (2018), 11 (5), 2357-2365CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Designing active sites and engineering electronic properties of heterogeneous catalysts are both promising strategies that can be employed to enhance the catalytic activity for CO2 hydrogenation. Herein, we report RhCo porous nanospheres with a high d. of accessible grain boundaries as active sites for improved catalytic performance in the hydrogenation of CO2 to methanol. The porous nanosphere morphol. feature allows for a high population of grain boundaries to be accessible to the reactants, thereby providing sufficient active sites for the catalytic reaction. Moreover, in-situ X-ray photoelectron spectroscope (XPS) results revealed the creation of neg. charged Rh surface atoms that promoted the activation of CO2 to generate CO2δ- and methoxy intermediates. The obtained RhCo porous nanospheres exhibited remarkable low-temp. catalytic activity with a turnover frequency (TOFRh) of 612 h-1, which was 6.1 and 2.5 times higher than that of Rh/C and RhCo nanoparticles, resp. This work not only develops an efficient catalyst for CO2 hydrogenation, but also demonstrates a potential approach for the modulation of active sites and electronic properties. [Figure not available: see fulltext.].
- 17Li, H.; Wang, L.; Dai, Y.; Pu, Z.; Lao, Z.; Chen, Y.; Wang, M.; Zheng, X.; Zhu, J.; Zhang, W.; Si, R.; Ma, C.; Zeng, J. Synergetic Interaction between Neighbouring Platinum Monomers in CO2 Hydrogenation. Nat. Nanotechnol. 2018, 13 (5), 411– 417, DOI: 10.1038/s41565-018-0089-zGoogle Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltlSlsLc%253D&md5=085ec1a07a2a3f89188c39fd3f6bdde5Synergetic interaction between neighbouring platinum monomers in CO2 hydrogenationLi, Hongliang; Wang, Liangbing; Dai, Yizhou; Pu, Zhengtian; Lao, Zhuohan; Chen, Yawei; Wang, Menglin; Zheng, Xusheng; Zhu, Junfa; Zhang, Wenhua; Si, Rui; Ma, Chao; Zeng, JieNature Nanotechnology (2018), 13 (5), 411-417CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Exploring the interaction between two neighboring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighboring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighboring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the at. dispersion of Pt. Mechanistic studies reveal that neighboring Pt monomers not only worked in synergy to vary the reaction barrier, but also underwent distinct reaction paths compared with isolated monomers. Isolated Pt monomers favor the conversion of CO2 into methanol without the formation of formic acid, whereas CO2 is hydrogenated stepwise into formic acid and methanol for neighboring Pt monomers. The discovery of the synergetic interaction between neighboring monomers may create a new path for manipulating catalytic properties.
- 18Kanega, R.; Onishi, N.; Tanaka, S.; Kishimoto, H.; Himeda, Y. Catalytic Hydrogenation of CO2 to Methanol Using Multinuclear Iridium Complexes in a Gas–Solid Phase Reaction. J. Am. Chem. Soc. 2021, 143 (3), 1570– 1576, DOI: 10.1021/jacs.0c11927Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXpvF2quw%253D%253D&md5=8e56f3859ae7c0f21a3baff7187383cbCatalytic Hydrogenation of CO2 to Methanol Using Multinuclear Iridium Complexes in a Gas-Solid Phase ReactionKanega, Ryoichi; Onishi, Naoya; Tanaka, Shinji; Kishimoto, Haruo; Himeda, YuichiroJournal of the American Chemical Society (2021), 143 (3), 1570-1576CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A novel approach is reported toward the catalytic hydrogenation of CO2 to methanol performed in the gas-solid phase using multinuclear iridium complexes at low temp. (30-80°). Although homogeneous CO2 hydrogenation in water catalyzed by amide-based iridium catalysts provided only a negligible amt. of methanol, the combination of a multinuclear catalyst and gas-solid phase reaction conditions led to the effective prodn. of methanol from CO2. The catalytic activities of the multinuclear catalyst were dependent on the relative configuration of each active species. Conveniently, methanol obtained from the gas phase could be easily isolated from the catalyst without contamination with CO, CH4, or formic acid (FA). The catalyst can be recycled in a batchwise manner via gas release and filling. A final turnover no. of 113 was obtained upon reusing the catalyst at 60° and 4 MPa of H2/CO2 (3:1). The high reactivity of this system has been attributed to hydride complex formation upon exposure to H2 gas, suppression of the liberation of FA under gas-solid phase reaction conditions, and intramol. multiple hydride transfer to CO2 by the multinuclear catalyst.
- 19Hu, J.; Yu, L.; Deng, J.; Wang, Y.; Cheng, K.; Ma, C.; Zhang, Q.; Wen, W.; Yu, S.; Pan, Y.; Yang, J.; Ma, H.; Qi, F.; Wang, Y.; Zheng, Y.; Chen, M.; Huang, R.; Zhang, S.; Zhao, Z.; Mao, J.; Meng, X.; Ji, Q.; Hou, G.; Han, X.; Bao, X.; Wang, Y.; Deng, D. Sulfur Vacancy-Rich MoS2 as a Catalyst for the Hydrogenation of CO2 to Methanol. Nat. Catal 2021, 4 (3), 242– 250, DOI: 10.1038/s41929-021-00584-3Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhs12itLbP&md5=b8517e54afa4522201c9558da2d9f2c3Sulfur vacancy-rich MoS2 as a catalyst for the hydrogenation of CO2 to methanolHu, Jingting; Yu, Liang; Deng, Jiao; Wang, Yong; Cheng, Kang; Ma, Chao; Zhang, Qinghong; Wen, Wu; Yu, Shengsheng; Pan, Yang; Yang, Jiuzhong; Ma, Hao; Qi, Fei; Wang, Yongke; Zheng, Yanping; Chen, Mingshu; Huang, Rui; Zhang, Shuhong; Zhao, Zhenchao; Mao, Jun; Meng, Xiangyu; Ji, Qinqin; Hou, Guangjin; Han, Xiuwen; Bao, Xinhe; Wang, Ye; Deng, DehuiNature Catalysis (2021), 4 (3), 242-250CODEN: NCAACP; ISSN:2520-1158. (Nature Research)The low-temp. hydrogenation of CO2 to methanol is of great significance for the recycling of this greenhouse gas to valuable products, however, it remains a great challenge due to the trade-off between catalytic activity and selectivity. Here, we report that CO2 can dissoc. at sulfur vacancies in MoS2 nanosheets to yield surface-bound CO and O at room temp., thus enabling a highly efficient low-temp. hydrogenation of CO2 to methanol. Multiple in situ spectroscopic and microscopic characterizations combined with theor. calcns. demonstrated that in-plane sulfur vacancies drive the selective hydrogenation of CO2 to methanol by inhibiting deep hydrogenolysis to methane, whereas edge vacancies facilitate excessive hydrogenation to methane. At 180°C, the catalyst achieved a 94.3% methanol selectivity at a CO2 conversion of 12.5% over the in-plane sulfur vacancy-rich MoS2 nanosheets, which notably surpasses those of previously reported catalysts. This catalyst exhibited high stability for over 3,000 h without any deactivation, rendering it a promising candidate for industrial application.
- 20Uvdal, P.; Weldon, M. K.; Friend, C. M. Adsorbate Symmetry and Fermi Resonances of Methoxide Adsorbed on Mo(110) as Studied by Surface Infrared Spectroscopy. Phys. Rev. B 1994, 50 (16), 12258– 12261, DOI: 10.1103/PhysRevB.50.12258Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXhvFCrs78%253D&md5=7c090f6dc20e7f076dc460327f88ae08Adsorbate symmetry and Fermi resonances of methoxide adsorbed on Mo(110) as studied by surface infrared spectroscopyUvdal, P.; Weldon, M. K.; Friend, C. M.Physical Review B: Condensed Matter (1994), 50 (16), 12258-61CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)It is conclusively demonstrated using surface IR spectroscopy, in combination with selective isotopic labeling, that methoxy coordinates with C3ν symmetry on Mo(110), at coverages below 0.17 ML. The existence of intense Fermi resonances in the C-H stretch region of adsorbed CH3O is firmly established. By application of these observations to previous studies of methoxy on the low-index planes of copper and nickel, the disparity between the adsorbate geometry predicted by IR spectroscopy and that deduced from photoelectron studies is removed.
- 21Ojelade, O. A.; Zaman, S. F. A Review on Pd Based Catalysts for CO2 Hydrogenation to Methanol: In-Depth Activity and DRIFTS Mechanistic Study. Catal. Surv Asia 2020, 24 (1), 11– 37, DOI: 10.1007/s10563-019-09287-zGoogle Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhvF2gtL7E&md5=041c9068f892351b2127510473010218A Review on Pd Based Catalysts for CO2 Hydrogenation to Methanol: In-Depth Activity and DRIFTS Mechanistic StudyOjelade, Opeyemi A.; Zaman, Sharif F.Catalysis Surveys from Asia (2020), 24 (1), 11-37CODEN: CSAABF; ISSN:1571-1013. (Springer)Abstr.: Global warming, the environmental curse, created mainly by anthropogenic uses of fossil resources causing an excessive amt. of CO2 emission in the earth's atm. Scientists are focusing to utilize CO2 to produce value added chems., i.e. methanol, DME, formic acid, etc. to reduce the effect of this greenhouse gas (GHG) and also provide an alternative carbon source and carbon neutral pathway for valuable chems. Despite significant achievements so far on the conversion of CO2 to methanol via hydrogenation over Cu-ZnO-Al2O3 catalyst, palladium and palladium based bimetallic catalysts showed a superior activity (> 10% CO2 conversion) and selectivity (∼ 100%) to methanol over Cu based catalysts esp. at low pressure (≤ 30 bar) and low temp. (≤ 250 °C). The alloying effect of Pd with the support ZnO, ZrO2, Ga2O3, etc. forming PdZn, PdZr2, PdGa species, which are identified as the main active phase of methanol synthesis. Also, reducible oxidic supports like CeO2, ZrO2, Ga2O3, etc. played important roles in adsorbing and activating CO2 as CO and or CO3- over the surface and hydrogenated to formate species, which has been regarded as the pivotal intermediate for methanol synthesis. Though there are challenges involving the costs of noble metal palladium, hydrogen prodn. from renewable sources and carbon capture and storage (CSS) processes. There are several review articles on CO2 hydrogenation to methanol in the past few years but none of the existing review articles uniquely dealt with Pd-based catalysts. On this premise, this article presents a brief review comprising catalytic activity of Pd and Pd based bimetallic catalysts, effects of supports and promoters, reaction mechanism (DRIFTS studies) and perspectives on future researches necessary to achieve industrial acceptability of Pd-based catalyst for CO2 hydrogenation to methanol. Graphic Abstr.: [Figure not available: see fulltext.].
- 22Hirano, T.; Kazahaya, Y.; Nakamura, A.; Miyao, T.; Naito, S. Remarkable Effect of Addition of In and Pb on the Reduction of N2O by CO over SiO2 Supported Pd Catalysts. Catal. Lett. 2007, 117 (1), 73– 78, DOI: 10.1007/s10562-007-9109-6Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXptVGmurw%253D&md5=221cd2fc30255300973f095664f5411eRemarkable effect of addition of In and Pb on the reduction of N2O by CO over SiO2 supported Pd catalystsHirano, Takashi; Kazahaya, Yuiko; Nakamura, Akio; Miyao, Toshihiro; Naito, ShuichiCatalysis Letters (2007), 117 (1-2), 73-78CODEN: CALEER; ISSN:1011-372X. (Springer)The effect of addn. of In and Pb on the redn. of N2O by CO was studied over SiO2 supported Pd catalysts, using a closed gas circulation system as well as in-situ IR spectroscopy. Formation of intermetallic compds. such as Pd0.48In0.52, Pd3Pb and Pd3Pb2 was obsd. which caused a drastic enhancement of the rate of N2 formation. The IR spectroscopic analyses revealed a weakening of the adsorption strength of CO on Pd metal by the formation of intermetallic compds., which is likely the main reason for the enhancement of the reaction rate. From a kinetic investigation as well as in situ FT-IR observation during the N2O-CO reaction, a redox mechanism was proposed involving the oxidn. of the surface by N2O followed by its redn. by CO. Over Pd/SiO2, the former process seems to be the rate limiting step because of the inhibition of N2O activation by strongly adsorbed CO. By adding In or Pb, the rate limiting step shifted to the latter process, which resulted in a large enhancement in the rate of N2 formation.
- 23Ebbesen, S. D.; Mojet, B. L.; Lefferts, L. The Influence of Water and PH on Adsorption and Oxidation of CO on Pd/Al2O3─an Investigation by Attenuated Total Reflection Infrared Spectroscopy. Phys. Chem. Chem. Phys. 2009, 11 (4), 641– 649, DOI: 10.1039/B814605EGoogle Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1SitA%253D%253D&md5=a3a73008c3ecfcafdcb7b61659eaf3a4The influence of water and pH on adsorption and oxidation of CO on Pd/Al2O3-an investigation by attenuated total reflection infrared spectroscopyEbbesen, Sune D.; Mojet, Barbara L.; Lefferts, LeonPhysical Chemistry Chemical Physics (2009), 11 (4), 641-649CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Adsorption and oxidn. of carbon monoxide over a Pd/Al2O3 catalyst layer was studied both in gas phase and water. Both adsorption and oxidn. of CO are significantly affected by the presence of liq. water. Water influences the potential of the metal particles as well as the dipole moment of the adsorbed CO mol. directly, which is reflected both in large red shifts and a higher IR intensity when expts. are carried out in water. Also, the rate of CO oxidn. increases significantly by both the presence of water and by increasing the pH. Enhancement of the oxidn. rate is attributed to a weakening of the CO bond by increasing potential of the metal particle, similar to CO oxidn. over Pt/Al2O3 as recently published. However, on Pd/Al2O3 the oxidn. of palladium is clearly promoted at increasing pH, further enhancing the oxidn. of CO over Pd/Al2O3.
- 24Guil-López, R.; Mota, N.; Llorente, J.; Millán, E.; Pawelec, B.; Fierro, J. L. G.; Navarro, R. M. Methanol Synthesis from CO2: A Review of the Latest Developments in Heterogeneous Catalysis. Materials 2019, 12 (23), 3902, DOI: 10.3390/ma12233902Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXovVWhsL8%253D&md5=446797ab8ac9e7f5d90dfc89acf88286Methanol synthesis from CO2: a review of the latest developments in heterogeneous catalysisGuil-Lopez, R.; Mota, N.; Llorente, J.; Millan, E.; Pawelec, B.; Fierro, J. L. G.; Navarro, R. M.Materials (2019), 12 (23), 3902CODEN: MATEG9; ISSN:1996-1944. (MDPI AG)Technol. approaches which enable the effective utilization of CO2 for manufg. value-added chems. and fuels can help to solve environmental problems derived from large CO2 emissions assocd. with the use of fossil fuels. One of the most interesting products that can be synthesized from CO2 is methanol, since it is an industrial commodity used in several chem. products and also an efficient transportation fuel. In this review, we highlight the recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to methanol. The main efforts focused on the improvement of conventional Cu/ZnO based catalysts and the development of new catalytic systems targeting the specific needs for CO2 to methanol reactions (unfavorable thermodn., prodn. of high amt. of water and high methanol selectivity under high or full CO2 conversion). Major studies on the development of active and selective catalysts based on thermodn., mechanisms, nano-synthesis and catalyst design (active phase, promoters, supports, etc.) are highlighted in this review. Finally, a summary concerning future perspectives on the research and development of efficient heterogeneous catalysts for methanol synthesis from CO2 will be presented.
- 25Kattel, S.; Yan, B.; Yang, Y.; Chen, J. G.; Liu, P. Optimizing Binding Energies of Key Intermediates for CO2 Hydrogenation to Methanol over Oxide-Supported Copper. J. Am. Chem. Soc. 2016, 138 (38), 12440– 12450, DOI: 10.1021/jacs.6b05791Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVWlt7vE&md5=652b3c2ec5e71b056cc9a953759477c0Optimizing Binding Energies of Key Intermediates for CO2 Hydrogenation to Methanol over Oxide-Supported CopperKattel, Shyam; Yan, Binhang; Yang, Yixiong; Chen, Jingguang G.; Liu, PingJournal of the American Chemical Society (2016), 138 (38), 12440-12450CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Rational optimization of catalytic performance has been one of the major challenges in catalysis. Here we report a bottom-up study on the ability of TiO2 and ZrO2 to optimize the CO2 conversion to methanol on Cu, using combined d. functional theory (DFT) calcns., kinetic Monte Carlo (KMC) simulations, in situ diffuse reflectance IR Fourier transform spectroscopy (DRIFTS) measurements, and steady-state flow reactor tests. The theor. results from DFT and KMC agree with in situ DRIFTS measurements, showing that both TiO2 and ZrO2 help to promote methanol synthesis on Cu via carboxyl intermediates and the reverse water-gas-shift (RWGS) pathway; the formate intermediates, on the other hand, likely act as a spectator eventually. The origin of the superior promoting effect of ZrO2 is assocd. with the fine-tuning capability of reduced Zr3+ at the interface, being able to bind the key reaction intermediates, e.g. *CO2, *CO, *HCO, and *H2CO, moderately to facilitate methanol formation. This study demonstrates the importance of synergy between theory and expts. to elucidate the complex reaction mechanisms of CO2 hydrogenation for the realization of a better catalyst by design.
- 26Brix, F.; Desbuis, V.; Piccolo, L.; Gaudry, É. Tuning Adsorption Energies and Reaction Pathways by Alloying: PdZn versus Pd for CO2 Hydrogenation to Methanol. J. Phys. Chem. Lett. 2020, 11 (18), 7672– 7678, DOI: 10.1021/acs.jpclett.0c02011Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFyis7zJ&md5=5a5f8a942a79eb756cb352b810bdd611Tuning Adsorption Energies and Reaction Pathways by Alloying: PdZn versus Pd for CO2 Hydrogenation to MethanolBrix, Florian; Desbuis, Valentin; Piccolo, Laurent; Gaudry, EmilieJournal of Physical Chemistry Letters (2020), 11 (18), 7672-7678CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The tunability offered by alloying different elements is useful to design catalysts with greater activity, selectivity, and stability than single metals. By comparing the Pd(111) and PdZn(111) model catalysts for CO2 hydrogenation to methanol, we show that intermetallic alloying is a possible strategy to control the reaction pathway from the tuning of adsorbate binding energies. In comparison to Pd, the strong electron-donor character of PdZn weakens the adsorption of carbon-bound species and strengthens the binding of oxygen-bound species. As a consequence, the first step of CO2 hydrogenation more likely leads to the formate intermediate on PdZn, while the carboxyl intermediate is preferentially formed on Pd. This results in the opening of a pathway from carbon dioxide to methanol on PdZn similar to that previously proposed on Cu. These findings rationalize the superiority of PdZn over Pd for CO2 conversion into methanol and suggest guidance for designing more efficient catalysts by promoting the proper reaction intermediates.
- 27Lin, S.; Ma, J.; Ye, X.; Xie, D.; Guo, H. CO Hydrogenation on Pd(111): Competition between Fischer–Tropsch and Oxygenate Synthesis Pathways. J. Phys. Chem. C 2013, 117 (28), 14667– 14676, DOI: 10.1021/jp404509vGoogle Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpslKisb4%253D&md5=9bad6939ef331a8a1734ebe6d00e772fCO Hydrogenation on Pd(111): Competition between Fischer-Tropsch and Oxygenate Synthesis PathwaysLin, Sen; Ma, Jianyi; Ye, Xinxin; Xie, Daiqian; Guo, HuaJournal of Physical Chemistry C (2013), 117 (28), 14667-14676CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The hydrogenation of CO on Pd can lead to methane via the Fischer-Tropsch process and methanol via oxygenate synthesis. Despite the fact that the former is thermodynamically favored, the catalysis is mostly selective to the latter. Given the importance of methanol synthesis in both industry applications and fundamental understanding of heterogeneous catalysis, it is highly desirable to understand the mechanism and selectivity of CO hydrogenation on Pd catalysts. In this work, this process is studied on Pd(111) using periodic plane-wave d. functional theory and kinetic Monte Carlo simulations. The barriers and reaction energies for the methanol and methane formation are systematically explored. Our results suggest that methanol is formed via CO* → CHO* → HCOH* → CH2OH* → CH3OH*. The HCOH* and CH2OH* intermediates, which feature a C-O single bond, were found to possess the lowest barriers for C-O bond fission, but they are still higher than those in methanol formation, thus confirming the kinetic origin of the exptl. obsd. selectivity of the Pd catalysts toward methanol.
- 28Sugiyama, H.; Nakao, T.; Miyazaki, M.; Abe, H.; Niwa, Y.; Kitano, M.; Hosono, H. Low-Temperature Methanol Synthesis by a Cu-Loaded LaH2+x Electride. ACS Catal. 2022, 12 (20), 12572– 12581, DOI: 10.1021/acscatal.2c03662Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XisFWqur3I&md5=56d900285d9a08a3f8f98f81d9a97fceLow-Temperature Methanol Synthesis by a Cu-Loaded LaH ElectrideSugiyama, Hironobu; Nakao, Takuya; Miyazaki, Masayoshi; Abe, Hitoshi; Niwa, Yasuhiro; Kitano, Masaaki; Hosono, HideoACS Catalysis (2022), 12 (20), 12572-12581CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)Methanol is a key chem. in C1 chem. and energy carrier. The industrial synthesis of methanol uses a heterogeneous catalyst, Cu/ZnO/Al2O3, under harsh conditions of high temp. and high pressure. Here, we propose a design concept for a catalyst to achieve low-temp. synthesis of methanol and report that Cu-loaded rare-earth hydrides (Cu/REH2) work as effective catalysts for methanol synthesis from CO and H2 at temps. below 100°C, where the conventional Cu/ZnO/Al2O3 industrial catalyst does not work well. This catalytic activity is due to neg. charged Cu sites that originate from the highly electron-donating support material and hydride ions directly reactive with CO. The activation energy and turn over frequency for the catalyst are less than half and ~ 20 times higher than that for conventional Cu-based catalysts, resp. The present work demonstrates that anionic electrons with a low work function, the metallic nature of the support material, and hydride ions in the support play key roles for low-temp. methanol synthesis.
- 29Stangeland, K.; Li, H.; Yu, Z. Thermodynamic Analysis of Chemical and Phase Equilibria in CO2 Hydrogenation to Methanol, Dimethyl Ether, and Higher Alcohols. Ind. Eng. Chem. Res. 2018, 57 (11), 4081– 4094, DOI: 10.1021/acs.iecr.7b04866Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjs1KjtL8%253D&md5=a9da8b9b3a6862f37a25b9160cc60806Thermodynamic Analysis of Chemical and Phase Equilibria in CO2 Hydrogenation to Methanol, Dimethyl Ether, and Higher AlcoholsStangeland, Kristian; Li, Hailong; Yu, ZhixinIndustrial & Engineering Chemistry Research (2018), 57 (11), 4081-4094CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)CO2 hydrogenation can lead to the formation of various products, of which methanol, di-Me ether (DME) and ethanol have received great attention. In this study, a comprehensive thermodn. anal. of CO2 hydrogenation in binary (methanol/CO) and ternary product systems (methanol/CO with DME or ethanol) is conducted in Aspen Plus by the Gibbs free energy minimization method combined with phase equil. calcns. Product condensation can be utilized to circumvent thermodn. restrictions on product yield. Significant improvements in CO2 conversion can be achieved by operating at conditions favorable for product condensation, whereas the selectivity is mildly affected. The relevance of the results herein is discussed with regards to recent advances in catalysis and process design for CO2 hydrogenation. Our study highlights the importance of obtaining a thorough understanding of the thermodn. of CO2 hydrogenation processes, which will be crit. for developing potential breakthrough technol. applicable at the industrial scale.
Cited By
This article is cited by 5 publications.
- Partha Pratim Mondal, Sayantan Sarkar, Manpreet Singh, Subhadip Neogi. Temperature-Variant CO2 Separation in Entangled Metal-Organic Framework with Carboxamide Functionality-Fueled Atmospheric-Pressure Cycloaddition and Size-Exclusive Tandem Knoevenagel Condensation. ACS Sustainable Chemistry & Engineering 2024, 12
(42)
, 15432-15446. https://doi.org/10.1021/acssuschemeng.4c04353
- Naoya Onishi, Yuichiro Himeda. Toward Methanol Production by CO2 Hydrogenation beyond Formic Acid Formation. Accounts of Chemical Research 2024, 57
(19)
, 2816-2825. https://doi.org/10.1021/acs.accounts.4c00411
- Huanyu Zhou, Shuanglin Zhang, Yan Shao, Shoujie Liu, Xiaolei Fan, Huanhao Chen. Relationship between Structural Properties of the Unsupported Ni5Ga3 Catalyst and Methanol Synthesis Activity. Industrial & Engineering Chemistry Research 2024, 63
(16)
, 6974-6984. https://doi.org/10.1021/acs.iecr.4c00241
- Shenghui Zhou, Mohammadreza Kosari, Hua Chun Zeng. Boosting CO2 Hydrogenation to Methanol over Monolayer MoS2 Nanotubes by Creating More Strained Basal Planes. Journal of the American Chemical Society 2024, 146
(14)
, 10032-10043. https://doi.org/10.1021/jacs.4c00781
- Likang Zhang, Yao Zhong, Jun Wang, Zheling Zeng, Shuguang Deng, Ji-Jun Zou, Qiang Deng. Intermetallic Palladium–Zinc Nanoparticles for the Ultraselective Hydrogenative Rearrangement of Furan Compounds. ACS Catalysis 2023, 13
(20)
, 13205-13214. https://doi.org/10.1021/acscatal.3c03189
Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.
Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.
The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.
Recommended Articles
References
This article references 29 other publications.
- 1Höök, M.; Tang, X. Depletion of Fossil Fuels and Anthropogenic Climate Change─A Review. Energy Policy 2013, 52, 797– 809, DOI: 10.1016/j.enpol.2012.10.046There is no corresponding record for this reference.
- 2Artz, J.; Müller, T. E.; Thenert, K.; Kleinekorte, J.; Meys, R.; Sternberg, A.; Bardow, A.; Leitner, W. Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment. Chem. Rev. 2018, 118 (2), 434– 504, DOI: 10.1021/acs.chemrev.7b004352https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFemsrbL&md5=5348e984489e8e3e18368ed6a9088ec1Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle AssessmentArtz, Jens; Mueller, Thomas E.; Thenert, Katharina; Kleinekorte, Johanna; Meys, Raoul; Sternberg, Andre; Bardow, Andre; Leitner, WalterChemical Reviews (Washington, DC, United States) (2018), 118 (2), 434-504CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chems. and even to specialty products with biol. activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined anal. of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochem. value chain. This anal. and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem "CO2 emissions" from todays' industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future prodn. Thus, the motivation to develop CO2-based chem. does not depend primarily on the abs. amt. of CO2 emissions that can be remediated by a single technol. Rather, CO2-based chem. is stimulated by the significance of the relative improvement in carbon balance and other crit. factors defining the environmental impact of chem. prodn. in all relevant sectors in accord with the principles of green chem.
- 3Gao, P.; Li, S.; Bu, X.; Dang, S.; Liu, Z.; Wang, H.; Zhong, L.; Qiu, M.; Yang, C.; Cai, J.; Wei, W.; Sun, Y. Direct Conversion of CO2 into Liquid Fuels with High Selectivity over a Bifunctional Catalyst. Nature Chem. 2017, 9 (10), 1019– 1024, DOI: 10.1038/nchem.27943https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVSjt7bI&md5=4ef37e087edf5dfbaf26bcd93105f584Direct conversion of CO2 into liquid fuels with high selectivity over a bifunctional catalystGao, Peng; Li, Shenggang; Bu, Xianni; Dang, Shanshan; Liu, Ziyu; Wang, Hui; Zhong, Liangshu; Qiu, Minghuang; Yang, Chengguang; Cai, Jun; Wei, Wei; Sun, YuhanNature Chemistry (2017), 9 (10), 1019-1024CODEN: NCAHBB; ISSN:1755-4330. (Nature Research)Although considerable progress was made in CO2 hydrogenation to various C1 chems., it is still a great challenge to synthesize value-added products with ≥2 carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here the authors present a bifunctional catalyst composed of reducible In oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%). The O vacancies on the In2O3 surfaces activate CO2 and H to form MeOH, and C-C coupling subsequently occurs inside zeolite pores to produce gasoline-range hydrocarbons with a high octane no. The proximity of these 2 components plays a crucial role in suppressing the undesired reverse water gas shift reaction and giving a high selectivity for gasoline-range hydrocarbons. Also, the pellet catalyst exhibits a much better performance during an industry-relevant test, which suggests promising prospects for industrial applications.
- 4Kim, D.-Y.; Ham, H.; Chen, X.; Liu, S.; Xu, H.; Lu, B.; Furukawa, S.; Kim, H.-H.; Takakusagi, S.; Sasaki, K.; Nozaki, T. Cooperative Catalysis of Vibrationally Excited CO2 and Alloy Catalyst Breaks the Thermodynamic Equilibrium Limitation. J. Am. Chem. Soc. 2022, 144 (31), 14140– 14149, DOI: 10.1021/jacs.2c037644https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhvFWhsrrK&md5=3f49b0d802c776e8e9a81cd2a65526e2Cooperative Catalysis of Vibrationally Excited CO2 and Alloy Catalyst Breaks the Thermodynamic Equilibrium LimitationKim, Dae-Yeong; Ham, Hyungwon; Chen, Xiaozhong; Liu, Shuai; Xu, Haoran; Lu, Bang; Furukawa, Shinya; Kim, Hyun-Ha; Takakusagi, Satoru; Sasaki, Koichi; Nozaki, TomohiroJournal of the American Chemical Society (2022), 144 (31), 14140-14149CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Using nonthermal plasma (NTP) to promote CO2 hydrogenation is one of the most promising approaches that overcome the limitations of conventional thermal catalysis. However, the catalytic surface reaction dynamics of NTP-activated species are still under debate. The NTP-activated CO2 hydrogenation was investigated in Pd2Ga/SiO2 alloy catalysts and compared to thermal conditions. Although both thermal and NTP conditions showed close to 100% CO selectivity, it is worth emphasizing that when activated by NTP, CO2 conversion not only improves more than 2-fold under thermal conditions but also breaks the thermodn. equil. limitation. Mechanistic insights into NTP-activated species and alloy catalyst surface were investigated by using in situ transmission IR spectroscopy, where catalyst surface species were identified during NTP irradn. Moreover, in in situ X-ray absorption fine-structure anal. under reaction conditions, the catalyst under NTP conditions not only did not undergo restructuring affecting CO2 hydrogenation but also could clearly rule out catalyst activation by heating. In situ characterizations of the catalysts during CO2 hydrogenation depict that vibrationally excited CO2 significantly enhances the catalytic reaction. The agreement of approaches combining exptl. studies and d. functional theory (DFT) calcns. substantiates that vibrationally excited CO2 reacts directly with hydrogen adsorbed on Pd sites while accelerating formate formation due to neighboring Ga sites. Moreover, DFT anal. deduces the key reaction pathway that the decompn. of monodentate formate is promoted by plasma-activated hydrogen species. This work enables the high designability of CO2 hydrogenation catalysts toward value-added chems. based on the electrification of chem. processes via NTP.
- 5Zhong, J.; Yang, X.; Wu, Z.; Liang, B.; Huang, Y.; Zhang, T. State of the Art and Perspectives in Heterogeneous Catalysis of CO2 Hydrogenation to Methanol. Chem. Soc. Rev. 2020, 49 (5), 1385– 1413, DOI: 10.1039/C9CS00614A5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksFens7w%253D&md5=78445dfba315564c750d268dd2296f70State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanolZhong, Jiawei; Yang, Xiaofeng; Wu, Zhilian; Liang, Binglian; Huang, Yanqiang; Zhang, TaoChemical Society Reviews (2020), 49 (5), 1385-1413CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. The ever-increasing amt. of anthropogenic carbon dioxide (CO2) emissions has resulted in great environmental impacts. The selective hydrogenation of CO2 to methanol, the first target in the liq. sunshine vision, not only effectively mitigates the CO2 emissions, but also produces value-added chems. and fuels. This crit. review provides a comprehensive view of the significant advances in heterogeneous catalysis for methanol synthesis through direct hydrogenation of CO2. The challenges in thermodn. are addressed first. Then the progress in conventional Cu-based catalysts is discussed in detail, with an emphasis on the structural, chem., and electronic promotions of supports and promoters, the prepn. methods and precursors of Cu-based catalysts, as well as the proposed models for active sites. We also provide an overview of the progress in noble metal-based catalysts, bimetallic catalysts including alloys and intermetallic compds., as well as hybrid oxides and other novel catalytic systems. The developments in mechanistic aspects, reaction conditions and optimization, as well as reactor designs and innovations are also included. The advances in industrial applications for methanol synthesis are further highlighted. Finally, a summary and outlook are provided.
- 6Martin, O.; Martín, A. J.; Mondelli, C.; Mitchell, S.; Segawa, T. F.; Hauert, R.; Drouilly, C.; Curulla-Ferré, D.; Pérez-Ramírez, J. Indium Oxide as a Superior Catalyst for Methanol Synthesis by CO2 Hydrogenation. Angew. Chem., Int. Ed. 2016, 55 (21), 6261– 6265, DOI: 10.1002/anie.2016009436https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xks1elurs%253D&md5=a6c662dc8dd8bd688ee5e3386221229aIndium Oxide as a Superior Catalyst for Methanol Synthesis by CO2 HydrogenationMartin, Oliver; Martin, Antonio J.; Mondelli, Cecilia; Mitchell, Sharon; Segawa, Takuya F.; Hauert, Roland; Drouilly, Charlotte; Curulla-Ferre, Daniel; Perez-Ramirez, JavierAngewandte Chemie, International Edition (2016), 55 (21), 6261-6265CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)MeOH synthesis by CO2 hydrogenation is attractive in view of avoiding the environmental implications assocd. with the prodn. of the traditional syngas feedstock and mitigating global warming. However, there still is a lack of efficient catalysts for such alternative processes. Herein, the authors unveil the high activity, 100% selectivity, and remarkable stability for 1000 h on stream of In2O3 supported on ZrO2 under industrially relevant conditions. This strongly contrasts to the benchmark Cu-ZnO-Al2O3 catalyst, which is unselective and experiences rapid deactivation. In-depth characterization of the In2O3-based materials points towards a mechanism rooted in the creation and annihilation of O vacancies as active sites, whose amt. can be modulated in situ by co-feeding CO and boosted through electronic interactions with the zirconia carrier. These results constitute a promising basis for the design of a prospective technol. for sustainable MeOH prodn.
- 7Jiang, X.; Nie, X.; Guo, X.; Song, C.; Chen, J. G. Recent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous Catalysis. Chem. Rev. 2020, 120 (15), 7984– 8034, DOI: 10.1021/acs.chemrev.9b007237https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXis1Whtr8%253D&md5=65a804dac18033b954e193f3354ecfbfRecent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous CatalysisJiang, Xiao; Nie, Xiaowa; Guo, Xinwen; Song, Chunshan; Chen, Jingguang G.Chemical Reviews (Washington, DC, United States) (2020), 120 (15), 7984-8034CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The utilization of fossil fuels has enabled an unprecedented era of prosperity and advancement of well-being for human society. However, the assocd. increase in anthropogenic carbon dioxide (CO2) emissions can neg. affect global temps. and ocean acidity. Moreover, fossil fuels are a limited resource and their depletion will ultimately force one to seek alternative carbon sources to maintain a sustainable economy. Converting CO2 into value-added chems. and fuels, using renewable energy, is one of the promising approaches in this regard. Major advances in energy-efficient CO2 conversion can potentially alleviate CO2 emissions, reduce the dependence on nonrenewable resources, and minimize the environmental impacts from the portions of fossil fuels displaced. Methanol (CH3OH) is an important chem. feedstock and can be used as a fuel for internal combustion engines and fuel cells, as well as a platform mol. for the prodn. of chems. and fuels. As one of the promising approaches, thermocatalytic CO2 hydrogenation to CH3OH via heterogeneous catalysis has attracted great attention in the past decades. Major progress has been made in the development of various catalysts including metals, metal oxides, and intermetallic compds. In addn., efforts are also put forth to define catalyst structures in nanoscale by taking advantage of nanostructured materials, which enables the tuning of the catalyst compn. and modulation of surface structures and potentially endows more promising catalytic performance in comparison to the bulk materials prepd. by traditional methods. Despite these achievements, significant challenges still exist in developing robust catalysts with good catalytic performance and long-term stability. In this review, a comprehensive overview is provided of the recent advances in this area, esp. focusing on structure-activity relationship, as well as the importance of combining catalytic measurements, in situ characterization, and theor. studies in understanding reaction mechanisms and identifying key descriptors for designing improved catalysts.
- 8Schneidewind, J.; Adam, R.; Baumann, W.; Jackstell, R.; Beller, M. Low-Temperature Hydrogenation of Carbon Dioxide to Methanol with a Homogeneous Cobalt Catalyst. Angew. Chem., Int. Ed. 2017, 56 (7), 1890– 1893, DOI: 10.1002/anie.2016090778https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsFWjtw%253D%253D&md5=bbce4fd6ca35545589b0dfda3de8369dLow-Temperature Hydrogenation of Carbon Dioxide to Methanol with a Homogeneous Cobalt CatalystSchneidewind, Jacob; Adam, Rosa; Baumann, Wolfgang; Jackstell, Ralf; Beller, MatthiasAngewandte Chemie, International Edition (2017), 56 (7), 1890-1893CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)We describe the 1st homogeneous non-noble metal catalyst for the hydrogenation of CO2 to methanol. The catalyst is formed in situ from [Co(acac)3], Triphos, and HNTf2 and enables the reaction to be performed at 100° without a decrease in activity. Kinetic studies suggest an inner-sphere mechanism, and in situ NMR and MS expts. reveal the formation of the active catalyst through slow removal of the acetylacetonate ligands.
- 9Ribeiro, A. P. C.; Martins, L. M. D. R. S.; Pombeiro, A. J. L. Carbon Dioxide-to-Methanol Single-Pot Conversion Using a C-Scorpionate Iron(II) Catalyst. Green Chem. 2017, 19 (20), 4811– 4815, DOI: 10.1039/C7GC01993A9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVGjurfP&md5=2cfbba29e0550784e3324ef2e0714ccaCarbon dioxide-to-methanol single-pot conversion using a C-scorpionate iron(II) catalystRibeiro, A. P. C.; Martins, L. M. D. R. S.; Pombeiro, A. J. L.Green Chemistry (2017), 19 (20), 4811-4815CODEN: GRCHFJ; ISSN:1463-9262. (Royal Society of Chemistry)The highly efficient eco-friendly synthesis of methanol (44% yield, TONs up to 2.3 × 103) directly from carbon dioxide is achieved by using H2 and the iron(II) scorpionate catalyst [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) in a solvent- or amine-free mild new protocol.
- 10Everett, M.; Wass, D. F. Highly Productive CO2 Hydrogenation to Methanol – a Tandem Catalytic Approach via Amide Intermediates. Chem. Commun. 2017, 53 (68), 9502– 9504, DOI: 10.1039/C7CC04613H10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVKiu7fJ&md5=645d9f5f54217fc6cd53e4a0f65a8dd1Highly productive CO2 hydrogenation to methanol - a tandem catalytic approach via amide intermediatesEverett, M.; Wass, D. F.Chemical Communications (Cambridge, United Kingdom) (2017), 53 (68), 9502-9504CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)A new system for CO2 redn. to methanol has been demonstrated using homogeneous ruthenium catalysts with a range of amine auxiliaries. Modification of this amine has a profound effect on the yield and selectivity of the reaction. A TON of 8900 and TOF of 4500 h-1 is achieved using a [RuCl2(Ph2PCH2CH2NHMe)2] catalyst with a diisopropylamine auxiliary.
- 11Poovan, F.; Chandrashekhar, V. G.; Natte, K.; Jagadeesh, R. V. Synergy between Homogeneous and Heterogeneous Catalysis. Catalysis Science & Technology 2022, 12 (22), 6623– 6649, DOI: 10.1039/D2CY00232A11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38Xhs12rsLzK&md5=4874fd881a22aa7d994562ee529c4ac3Synergy between homogeneous and heterogeneous catalysisPoovan, Fairoosa; Chandrashekhar, Vishwas G.; Natte, Kishore; Jagadeesh, Rajenahally V.Catalysis Science & Technology (2022), 12 (22), 6623-6649CODEN: CSTAGD; ISSN:2044-4753. (Royal Society of Chemistry)A review. Catalysis plays a decisive role in the advancement of sustainable processes in chem., pharmaceutical, and agrochem. industries as well as petrochem., material, and energy technologies. Notably, more than 80% of all chem. products involve catalysis processes in at least one stage in their manuf. Thus, for the modernization of chem. synthesis, the applicability of catalysts is crucial. Since the beginning of catalysis, a large no. of both homogeneous and heterogeneous catalysts have been developed and applied for all kinds of synthetic reactions. Among these, homogeneous complexes are active and selective but not stable and they are difficult to recycle or reuse. On the other hand, heterogeneous materials are quite stable and conveniently recyclable, but they exhibit lower activity and selectivity. In catalysis, the development of 'ideal' catalysts, which should be more active and selective as well as stable and easily recyclable, is of prime importance to produce all kinds of chems. including life science mols. In order to develop such catalyst systems, combining both homogeneous and heterogeneous catalysis concepts is considered to be a promising strategy. Applying this approach, special kinds of catalysts such as nanoparticles and single atoms as well as supported homogeneous complexes can be designed. These types of catalysts can overcome the limitations of both molecularly defined complexes and traditional heterogeneous materials. In this respect, in recent years more focus has been paid to the design of these classes of catalysts for org. synthesis. Consequently, in this review, we discuss the application of synergies between homogeneous and heterogeneous catalysis concepts in developing suitable catalysts that exhibit both activity and selectivity as well as stability and reusability. More specifically, selected examples and key achievements made on the prepn. and applications of nanoparticles, single atoms, and supported homogeneous complexes for org. transformations are summarized and discussed.
- 12Ting, K. W.; Toyao, T.; Siddiki, S. M. A. H.; Shimizu, K. Low-Temperature Hydrogenation of CO2 to Methanol over Heterogeneous TiO2-Supported Re Catalysts. ACS Catal. 2019, 9 (4), 3685– 3693, DOI: 10.1021/acscatal.8b0482112https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkvVSnu7o%253D&md5=b938d14735a3a7be5958e67842a655afLow-Temperature Hydrogenation of CO2 to Methanol over Heterogeneous TiO2-Supported Re CatalystsTing, Kah Wei; Toyao, Takashi; Siddiki, S. M. A. Hakim; Shimizu, Ken-ichiACS Catalysis (2019), 9 (4), 3685-3693CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)Hydrogenation of carbon dioxide (CO2) to methanol (MeOH) is an effective strategy for CO2 utilization. Because of a low equil. conversion of CO2 to MeOH at high temp., development of efficient catalytic CO2 hydrogenation processes that operate under low reaction temp. is of extreme importance. Herein, we report that TiO2-supported Re (Re(1)/TiO2; Re = 1 wt. %) promotes the selective hydrogenation of CO2 to MeOH (total TON based on Re = 44, MeOH selectivity = 82%) under mild conditions (pCO2 = 1 MPa; pH2 = 5 MPa; T = 150°). Both in terms of TON and methanol selectivity, the performance of Re(1)/TiO2 is superior to that of TiO2 catalysts loaded with other metals and to Re catalysts on other support materials. In addn., our investigations include the reaction mechanism and structure-activity relation for the catalytic system used in this study, suggesting that relatively reduced Re species (oxidn. state: 0-4) of subnanometer size serve as the catalytically active site for the formation of MeOH.
- 13Chen, Y.; Choi, S.; Thompson, L. T. Low Temperature CO2 Hydrogenation to Alcohols and Hydrocarbons over Mo2C Supported Metal Catalysts. J. Catal. 2016, 343, 147– 156, DOI: 10.1016/j.jcat.2016.01.01613https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitlChtrg%253D&md5=c0563197ea7a61c1a1ea6e1542c30b3bLow temperature CO2 hydrogenation to alcohols and hydrocarbons over Mo2C supported metal catalystsChen, Yuan; Choi, Saemin; Thompson, Levi T.Journal of Catalysis (2016), 343 (), 147-156CODEN: JCTLA5; ISSN:0021-9517. (Elsevier Inc.)A series of M/Mo2C (M = Cu, Pd, Co and Fe) were synthesized and evaluated for CO2 hydrogenation at 135-200 °C in liq. 1,4-dioxane solvent. The Mo2C served as both a support and a co-catalyst for CO2 hydrogenation, exhibiting turnover frequencies of 0.6 × 10-4 and 20 × 10-4 s-1 at 135 and 200 °C, resp. Methanol was the major product at 135 °C, while CH3OH, C2H5OH, and C2+ hydrocarbons were produced at 200 °C. The addn. of Cu and Pd onto the high surface area Mo2C enhanced the prodn. of CH3OH, while Co and Fe enhanced the prodn. of C2+ hydrocarbons. Results for CO2, CO, and CH3OH hydrogenation expts. suggested that CO2 was the primary source for CH3OH while CO was the intermediate to hydrocarbons during CO2 hydrogenation. Characterization of the spent M/Mo2C catalysts revealed very little change in the surface and bulk chemistries and structures, indicating their stability in the liq. environment.
- 14Khan, M. U.; Wang, L.; Liu, Z.; Gao, Z.; Wang, S.; Li, H.; Zhang, W.; Wang, M.; Wang, Z.; Ma, C.; Zeng, J. Pt3Co Octapods as Superior Catalysts of CO2 Hydrogenation. Angew. Chem., Int. Ed. 2016, 55 (33), 9548– 9552, DOI: 10.1002/anie.20160251214https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28bltFOjtg%253D%253D&md5=ae35237b5fe4a1b3d00f8cde40576257Pt3 Co Octapods as Superior Catalysts of CO2 HydrogenationKhan Munir Ullah; Wang Liangbing; Liu Zhao; Gao Zehua; Wang Shenpeng; Li Hongliang; Zhang Wenbo; Wang Menglin; Wang Zhengfei; Ma Chao; Zeng JieAngewandte Chemie (International ed. in English) (2016), 55 (33), 9548-52 ISSN:.As the electron transfer to CO2 is a critical step in the activation of CO2 , it is of significant importance to engineer the electronic properties of CO2 hydrogenation catalysts to enhance their activity. Herein, we prepared Pt3 Co nanocrystals with improved catalytic performance towards CO2 hydrogenation to methanol. Pt3 Co octapods, Pt3 Co nanocubes, Pt octapods, and Pt nanocubes were tested, and the Pt3 Co octapods achieved the best catalytic activity. Both the presence of multiple sharp tips and charge transfer between Pt and Co enabled the accumulation of negative charges on the Pt atoms in the vertices of the Pt3 Co octapods. Moreover, infrared reflection absorption spectroscopy confirmed that the high negative charge density at the Pt atoms in the vertices of the Pt3 Co octapods promotes the activation of CO2 and accordingly enhances the catalytic activity.
- 15Bai, S.; Shao, Q.; Feng, Y.; Bu, L.; Huang, X. Highly Efficient Carbon Dioxide Hydrogenation to Methanol Catalyzed by Zigzag Platinum–Cobalt Nanowires. Small 2017, 13 (22), 1604311, DOI: 10.1002/smll.201604311There is no corresponding record for this reference.
- 16Zheng, X.; Lin, Y.; Pan, H.; Wu, L.; Zhang, W.; Cao, L.; Zhang, J.; Zheng, L.; Yao, T. Grain Boundaries Modulating Active Sites in RhCo Porous Nanospheres for Efficient CO2 Hydrogenation. Nano Res. 2018, 11 (5), 2357– 2365, DOI: 10.1007/s12274-017-1841-716https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFOlsb3I&md5=e506b96b97f40aa4368ed868ed40dcddGrain boundaries modulating active sites in RhCo porous nanospheres for efficient CO2 hydrogenationZheng, Xusheng; Lin, Yue; Pan, Haibin; Wu, Lihui; Zhang, Wei; Cao, Linlin; Zhang, Jing; Zheng, Lirong; Yao, TaoNano Research (2018), 11 (5), 2357-2365CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Designing active sites and engineering electronic properties of heterogeneous catalysts are both promising strategies that can be employed to enhance the catalytic activity for CO2 hydrogenation. Herein, we report RhCo porous nanospheres with a high d. of accessible grain boundaries as active sites for improved catalytic performance in the hydrogenation of CO2 to methanol. The porous nanosphere morphol. feature allows for a high population of grain boundaries to be accessible to the reactants, thereby providing sufficient active sites for the catalytic reaction. Moreover, in-situ X-ray photoelectron spectroscope (XPS) results revealed the creation of neg. charged Rh surface atoms that promoted the activation of CO2 to generate CO2δ- and methoxy intermediates. The obtained RhCo porous nanospheres exhibited remarkable low-temp. catalytic activity with a turnover frequency (TOFRh) of 612 h-1, which was 6.1 and 2.5 times higher than that of Rh/C and RhCo nanoparticles, resp. This work not only develops an efficient catalyst for CO2 hydrogenation, but also demonstrates a potential approach for the modulation of active sites and electronic properties. [Figure not available: see fulltext.].
- 17Li, H.; Wang, L.; Dai, Y.; Pu, Z.; Lao, Z.; Chen, Y.; Wang, M.; Zheng, X.; Zhu, J.; Zhang, W.; Si, R.; Ma, C.; Zeng, J. Synergetic Interaction between Neighbouring Platinum Monomers in CO2 Hydrogenation. Nat. Nanotechnol. 2018, 13 (5), 411– 417, DOI: 10.1038/s41565-018-0089-z17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXltlSlsLc%253D&md5=085ec1a07a2a3f89188c39fd3f6bdde5Synergetic interaction between neighbouring platinum monomers in CO2 hydrogenationLi, Hongliang; Wang, Liangbing; Dai, Yizhou; Pu, Zhengtian; Lao, Zhuohan; Chen, Yawei; Wang, Menglin; Zheng, Xusheng; Zhu, Junfa; Zhang, Wenhua; Si, Rui; Ma, Chao; Zeng, JieNature Nanotechnology (2018), 13 (5), 411-417CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Exploring the interaction between two neighboring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighboring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighboring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the at. dispersion of Pt. Mechanistic studies reveal that neighboring Pt monomers not only worked in synergy to vary the reaction barrier, but also underwent distinct reaction paths compared with isolated monomers. Isolated Pt monomers favor the conversion of CO2 into methanol without the formation of formic acid, whereas CO2 is hydrogenated stepwise into formic acid and methanol for neighboring Pt monomers. The discovery of the synergetic interaction between neighboring monomers may create a new path for manipulating catalytic properties.
- 18Kanega, R.; Onishi, N.; Tanaka, S.; Kishimoto, H.; Himeda, Y. Catalytic Hydrogenation of CO2 to Methanol Using Multinuclear Iridium Complexes in a Gas–Solid Phase Reaction. J. Am. Chem. Soc. 2021, 143 (3), 1570– 1576, DOI: 10.1021/jacs.0c1192718https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXpvF2quw%253D%253D&md5=8e56f3859ae7c0f21a3baff7187383cbCatalytic Hydrogenation of CO2 to Methanol Using Multinuclear Iridium Complexes in a Gas-Solid Phase ReactionKanega, Ryoichi; Onishi, Naoya; Tanaka, Shinji; Kishimoto, Haruo; Himeda, YuichiroJournal of the American Chemical Society (2021), 143 (3), 1570-1576CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A novel approach is reported toward the catalytic hydrogenation of CO2 to methanol performed in the gas-solid phase using multinuclear iridium complexes at low temp. (30-80°). Although homogeneous CO2 hydrogenation in water catalyzed by amide-based iridium catalysts provided only a negligible amt. of methanol, the combination of a multinuclear catalyst and gas-solid phase reaction conditions led to the effective prodn. of methanol from CO2. The catalytic activities of the multinuclear catalyst were dependent on the relative configuration of each active species. Conveniently, methanol obtained from the gas phase could be easily isolated from the catalyst without contamination with CO, CH4, or formic acid (FA). The catalyst can be recycled in a batchwise manner via gas release and filling. A final turnover no. of 113 was obtained upon reusing the catalyst at 60° and 4 MPa of H2/CO2 (3:1). The high reactivity of this system has been attributed to hydride complex formation upon exposure to H2 gas, suppression of the liberation of FA under gas-solid phase reaction conditions, and intramol. multiple hydride transfer to CO2 by the multinuclear catalyst.
- 19Hu, J.; Yu, L.; Deng, J.; Wang, Y.; Cheng, K.; Ma, C.; Zhang, Q.; Wen, W.; Yu, S.; Pan, Y.; Yang, J.; Ma, H.; Qi, F.; Wang, Y.; Zheng, Y.; Chen, M.; Huang, R.; Zhang, S.; Zhao, Z.; Mao, J.; Meng, X.; Ji, Q.; Hou, G.; Han, X.; Bao, X.; Wang, Y.; Deng, D. Sulfur Vacancy-Rich MoS2 as a Catalyst for the Hydrogenation of CO2 to Methanol. Nat. Catal 2021, 4 (3), 242– 250, DOI: 10.1038/s41929-021-00584-319https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhs12itLbP&md5=b8517e54afa4522201c9558da2d9f2c3Sulfur vacancy-rich MoS2 as a catalyst for the hydrogenation of CO2 to methanolHu, Jingting; Yu, Liang; Deng, Jiao; Wang, Yong; Cheng, Kang; Ma, Chao; Zhang, Qinghong; Wen, Wu; Yu, Shengsheng; Pan, Yang; Yang, Jiuzhong; Ma, Hao; Qi, Fei; Wang, Yongke; Zheng, Yanping; Chen, Mingshu; Huang, Rui; Zhang, Shuhong; Zhao, Zhenchao; Mao, Jun; Meng, Xiangyu; Ji, Qinqin; Hou, Guangjin; Han, Xiuwen; Bao, Xinhe; Wang, Ye; Deng, DehuiNature Catalysis (2021), 4 (3), 242-250CODEN: NCAACP; ISSN:2520-1158. (Nature Research)The low-temp. hydrogenation of CO2 to methanol is of great significance for the recycling of this greenhouse gas to valuable products, however, it remains a great challenge due to the trade-off between catalytic activity and selectivity. Here, we report that CO2 can dissoc. at sulfur vacancies in MoS2 nanosheets to yield surface-bound CO and O at room temp., thus enabling a highly efficient low-temp. hydrogenation of CO2 to methanol. Multiple in situ spectroscopic and microscopic characterizations combined with theor. calcns. demonstrated that in-plane sulfur vacancies drive the selective hydrogenation of CO2 to methanol by inhibiting deep hydrogenolysis to methane, whereas edge vacancies facilitate excessive hydrogenation to methane. At 180°C, the catalyst achieved a 94.3% methanol selectivity at a CO2 conversion of 12.5% over the in-plane sulfur vacancy-rich MoS2 nanosheets, which notably surpasses those of previously reported catalysts. This catalyst exhibited high stability for over 3,000 h without any deactivation, rendering it a promising candidate for industrial application.
- 20Uvdal, P.; Weldon, M. K.; Friend, C. M. Adsorbate Symmetry and Fermi Resonances of Methoxide Adsorbed on Mo(110) as Studied by Surface Infrared Spectroscopy. Phys. Rev. B 1994, 50 (16), 12258– 12261, DOI: 10.1103/PhysRevB.50.1225820https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXhvFCrs78%253D&md5=7c090f6dc20e7f076dc460327f88ae08Adsorbate symmetry and Fermi resonances of methoxide adsorbed on Mo(110) as studied by surface infrared spectroscopyUvdal, P.; Weldon, M. K.; Friend, C. M.Physical Review B: Condensed Matter (1994), 50 (16), 12258-61CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)It is conclusively demonstrated using surface IR spectroscopy, in combination with selective isotopic labeling, that methoxy coordinates with C3ν symmetry on Mo(110), at coverages below 0.17 ML. The existence of intense Fermi resonances in the C-H stretch region of adsorbed CH3O is firmly established. By application of these observations to previous studies of methoxy on the low-index planes of copper and nickel, the disparity between the adsorbate geometry predicted by IR spectroscopy and that deduced from photoelectron studies is removed.
- 21Ojelade, O. A.; Zaman, S. F. A Review on Pd Based Catalysts for CO2 Hydrogenation to Methanol: In-Depth Activity and DRIFTS Mechanistic Study. Catal. Surv Asia 2020, 24 (1), 11– 37, DOI: 10.1007/s10563-019-09287-z21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhvF2gtL7E&md5=041c9068f892351b2127510473010218A Review on Pd Based Catalysts for CO2 Hydrogenation to Methanol: In-Depth Activity and DRIFTS Mechanistic StudyOjelade, Opeyemi A.; Zaman, Sharif F.Catalysis Surveys from Asia (2020), 24 (1), 11-37CODEN: CSAABF; ISSN:1571-1013. (Springer)Abstr.: Global warming, the environmental curse, created mainly by anthropogenic uses of fossil resources causing an excessive amt. of CO2 emission in the earth's atm. Scientists are focusing to utilize CO2 to produce value added chems., i.e. methanol, DME, formic acid, etc. to reduce the effect of this greenhouse gas (GHG) and also provide an alternative carbon source and carbon neutral pathway for valuable chems. Despite significant achievements so far on the conversion of CO2 to methanol via hydrogenation over Cu-ZnO-Al2O3 catalyst, palladium and palladium based bimetallic catalysts showed a superior activity (> 10% CO2 conversion) and selectivity (∼ 100%) to methanol over Cu based catalysts esp. at low pressure (≤ 30 bar) and low temp. (≤ 250 °C). The alloying effect of Pd with the support ZnO, ZrO2, Ga2O3, etc. forming PdZn, PdZr2, PdGa species, which are identified as the main active phase of methanol synthesis. Also, reducible oxidic supports like CeO2, ZrO2, Ga2O3, etc. played important roles in adsorbing and activating CO2 as CO and or CO3- over the surface and hydrogenated to formate species, which has been regarded as the pivotal intermediate for methanol synthesis. Though there are challenges involving the costs of noble metal palladium, hydrogen prodn. from renewable sources and carbon capture and storage (CSS) processes. There are several review articles on CO2 hydrogenation to methanol in the past few years but none of the existing review articles uniquely dealt with Pd-based catalysts. On this premise, this article presents a brief review comprising catalytic activity of Pd and Pd based bimetallic catalysts, effects of supports and promoters, reaction mechanism (DRIFTS studies) and perspectives on future researches necessary to achieve industrial acceptability of Pd-based catalyst for CO2 hydrogenation to methanol. Graphic Abstr.: [Figure not available: see fulltext.].
- 22Hirano, T.; Kazahaya, Y.; Nakamura, A.; Miyao, T.; Naito, S. Remarkable Effect of Addition of In and Pb on the Reduction of N2O by CO over SiO2 Supported Pd Catalysts. Catal. Lett. 2007, 117 (1), 73– 78, DOI: 10.1007/s10562-007-9109-622https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXptVGmurw%253D&md5=221cd2fc30255300973f095664f5411eRemarkable effect of addition of In and Pb on the reduction of N2O by CO over SiO2 supported Pd catalystsHirano, Takashi; Kazahaya, Yuiko; Nakamura, Akio; Miyao, Toshihiro; Naito, ShuichiCatalysis Letters (2007), 117 (1-2), 73-78CODEN: CALEER; ISSN:1011-372X. (Springer)The effect of addn. of In and Pb on the redn. of N2O by CO was studied over SiO2 supported Pd catalysts, using a closed gas circulation system as well as in-situ IR spectroscopy. Formation of intermetallic compds. such as Pd0.48In0.52, Pd3Pb and Pd3Pb2 was obsd. which caused a drastic enhancement of the rate of N2 formation. The IR spectroscopic analyses revealed a weakening of the adsorption strength of CO on Pd metal by the formation of intermetallic compds., which is likely the main reason for the enhancement of the reaction rate. From a kinetic investigation as well as in situ FT-IR observation during the N2O-CO reaction, a redox mechanism was proposed involving the oxidn. of the surface by N2O followed by its redn. by CO. Over Pd/SiO2, the former process seems to be the rate limiting step because of the inhibition of N2O activation by strongly adsorbed CO. By adding In or Pb, the rate limiting step shifted to the latter process, which resulted in a large enhancement in the rate of N2 formation.
- 23Ebbesen, S. D.; Mojet, B. L.; Lefferts, L. The Influence of Water and PH on Adsorption and Oxidation of CO on Pd/Al2O3─an Investigation by Attenuated Total Reflection Infrared Spectroscopy. Phys. Chem. Chem. Phys. 2009, 11 (4), 641– 649, DOI: 10.1039/B814605E23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1SitA%253D%253D&md5=a3a73008c3ecfcafdcb7b61659eaf3a4The influence of water and pH on adsorption and oxidation of CO on Pd/Al2O3-an investigation by attenuated total reflection infrared spectroscopyEbbesen, Sune D.; Mojet, Barbara L.; Lefferts, LeonPhysical Chemistry Chemical Physics (2009), 11 (4), 641-649CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Adsorption and oxidn. of carbon monoxide over a Pd/Al2O3 catalyst layer was studied both in gas phase and water. Both adsorption and oxidn. of CO are significantly affected by the presence of liq. water. Water influences the potential of the metal particles as well as the dipole moment of the adsorbed CO mol. directly, which is reflected both in large red shifts and a higher IR intensity when expts. are carried out in water. Also, the rate of CO oxidn. increases significantly by both the presence of water and by increasing the pH. Enhancement of the oxidn. rate is attributed to a weakening of the CO bond by increasing potential of the metal particle, similar to CO oxidn. over Pt/Al2O3 as recently published. However, on Pd/Al2O3 the oxidn. of palladium is clearly promoted at increasing pH, further enhancing the oxidn. of CO over Pd/Al2O3.
- 24Guil-López, R.; Mota, N.; Llorente, J.; Millán, E.; Pawelec, B.; Fierro, J. L. G.; Navarro, R. M. Methanol Synthesis from CO2: A Review of the Latest Developments in Heterogeneous Catalysis. Materials 2019, 12 (23), 3902, DOI: 10.3390/ma1223390224https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXovVWhsL8%253D&md5=446797ab8ac9e7f5d90dfc89acf88286Methanol synthesis from CO2: a review of the latest developments in heterogeneous catalysisGuil-Lopez, R.; Mota, N.; Llorente, J.; Millan, E.; Pawelec, B.; Fierro, J. L. G.; Navarro, R. M.Materials (2019), 12 (23), 3902CODEN: MATEG9; ISSN:1996-1944. (MDPI AG)Technol. approaches which enable the effective utilization of CO2 for manufg. value-added chems. and fuels can help to solve environmental problems derived from large CO2 emissions assocd. with the use of fossil fuels. One of the most interesting products that can be synthesized from CO2 is methanol, since it is an industrial commodity used in several chem. products and also an efficient transportation fuel. In this review, we highlight the recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO2 to methanol. The main efforts focused on the improvement of conventional Cu/ZnO based catalysts and the development of new catalytic systems targeting the specific needs for CO2 to methanol reactions (unfavorable thermodn., prodn. of high amt. of water and high methanol selectivity under high or full CO2 conversion). Major studies on the development of active and selective catalysts based on thermodn., mechanisms, nano-synthesis and catalyst design (active phase, promoters, supports, etc.) are highlighted in this review. Finally, a summary concerning future perspectives on the research and development of efficient heterogeneous catalysts for methanol synthesis from CO2 will be presented.
- 25Kattel, S.; Yan, B.; Yang, Y.; Chen, J. G.; Liu, P. Optimizing Binding Energies of Key Intermediates for CO2 Hydrogenation to Methanol over Oxide-Supported Copper. J. Am. Chem. Soc. 2016, 138 (38), 12440– 12450, DOI: 10.1021/jacs.6b0579125https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVWlt7vE&md5=652b3c2ec5e71b056cc9a953759477c0Optimizing Binding Energies of Key Intermediates for CO2 Hydrogenation to Methanol over Oxide-Supported CopperKattel, Shyam; Yan, Binhang; Yang, Yixiong; Chen, Jingguang G.; Liu, PingJournal of the American Chemical Society (2016), 138 (38), 12440-12450CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Rational optimization of catalytic performance has been one of the major challenges in catalysis. Here we report a bottom-up study on the ability of TiO2 and ZrO2 to optimize the CO2 conversion to methanol on Cu, using combined d. functional theory (DFT) calcns., kinetic Monte Carlo (KMC) simulations, in situ diffuse reflectance IR Fourier transform spectroscopy (DRIFTS) measurements, and steady-state flow reactor tests. The theor. results from DFT and KMC agree with in situ DRIFTS measurements, showing that both TiO2 and ZrO2 help to promote methanol synthesis on Cu via carboxyl intermediates and the reverse water-gas-shift (RWGS) pathway; the formate intermediates, on the other hand, likely act as a spectator eventually. The origin of the superior promoting effect of ZrO2 is assocd. with the fine-tuning capability of reduced Zr3+ at the interface, being able to bind the key reaction intermediates, e.g. *CO2, *CO, *HCO, and *H2CO, moderately to facilitate methanol formation. This study demonstrates the importance of synergy between theory and expts. to elucidate the complex reaction mechanisms of CO2 hydrogenation for the realization of a better catalyst by design.
- 26Brix, F.; Desbuis, V.; Piccolo, L.; Gaudry, É. Tuning Adsorption Energies and Reaction Pathways by Alloying: PdZn versus Pd for CO2 Hydrogenation to Methanol. J. Phys. Chem. Lett. 2020, 11 (18), 7672– 7678, DOI: 10.1021/acs.jpclett.0c0201126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFyis7zJ&md5=5a5f8a942a79eb756cb352b810bdd611Tuning Adsorption Energies and Reaction Pathways by Alloying: PdZn versus Pd for CO2 Hydrogenation to MethanolBrix, Florian; Desbuis, Valentin; Piccolo, Laurent; Gaudry, EmilieJournal of Physical Chemistry Letters (2020), 11 (18), 7672-7678CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The tunability offered by alloying different elements is useful to design catalysts with greater activity, selectivity, and stability than single metals. By comparing the Pd(111) and PdZn(111) model catalysts for CO2 hydrogenation to methanol, we show that intermetallic alloying is a possible strategy to control the reaction pathway from the tuning of adsorbate binding energies. In comparison to Pd, the strong electron-donor character of PdZn weakens the adsorption of carbon-bound species and strengthens the binding of oxygen-bound species. As a consequence, the first step of CO2 hydrogenation more likely leads to the formate intermediate on PdZn, while the carboxyl intermediate is preferentially formed on Pd. This results in the opening of a pathway from carbon dioxide to methanol on PdZn similar to that previously proposed on Cu. These findings rationalize the superiority of PdZn over Pd for CO2 conversion into methanol and suggest guidance for designing more efficient catalysts by promoting the proper reaction intermediates.
- 27Lin, S.; Ma, J.; Ye, X.; Xie, D.; Guo, H. CO Hydrogenation on Pd(111): Competition between Fischer–Tropsch and Oxygenate Synthesis Pathways. J. Phys. Chem. C 2013, 117 (28), 14667– 14676, DOI: 10.1021/jp404509v27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpslKisb4%253D&md5=9bad6939ef331a8a1734ebe6d00e772fCO Hydrogenation on Pd(111): Competition between Fischer-Tropsch and Oxygenate Synthesis PathwaysLin, Sen; Ma, Jianyi; Ye, Xinxin; Xie, Daiqian; Guo, HuaJournal of Physical Chemistry C (2013), 117 (28), 14667-14676CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The hydrogenation of CO on Pd can lead to methane via the Fischer-Tropsch process and methanol via oxygenate synthesis. Despite the fact that the former is thermodynamically favored, the catalysis is mostly selective to the latter. Given the importance of methanol synthesis in both industry applications and fundamental understanding of heterogeneous catalysis, it is highly desirable to understand the mechanism and selectivity of CO hydrogenation on Pd catalysts. In this work, this process is studied on Pd(111) using periodic plane-wave d. functional theory and kinetic Monte Carlo simulations. The barriers and reaction energies for the methanol and methane formation are systematically explored. Our results suggest that methanol is formed via CO* → CHO* → HCOH* → CH2OH* → CH3OH*. The HCOH* and CH2OH* intermediates, which feature a C-O single bond, were found to possess the lowest barriers for C-O bond fission, but they are still higher than those in methanol formation, thus confirming the kinetic origin of the exptl. obsd. selectivity of the Pd catalysts toward methanol.
- 28Sugiyama, H.; Nakao, T.; Miyazaki, M.; Abe, H.; Niwa, Y.; Kitano, M.; Hosono, H. Low-Temperature Methanol Synthesis by a Cu-Loaded LaH2+x Electride. ACS Catal. 2022, 12 (20), 12572– 12581, DOI: 10.1021/acscatal.2c0366228https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XisFWqur3I&md5=56d900285d9a08a3f8f98f81d9a97fceLow-Temperature Methanol Synthesis by a Cu-Loaded LaH ElectrideSugiyama, Hironobu; Nakao, Takuya; Miyazaki, Masayoshi; Abe, Hitoshi; Niwa, Yasuhiro; Kitano, Masaaki; Hosono, HideoACS Catalysis (2022), 12 (20), 12572-12581CODEN: ACCACS; ISSN:2155-5435. (American Chemical Society)Methanol is a key chem. in C1 chem. and energy carrier. The industrial synthesis of methanol uses a heterogeneous catalyst, Cu/ZnO/Al2O3, under harsh conditions of high temp. and high pressure. Here, we propose a design concept for a catalyst to achieve low-temp. synthesis of methanol and report that Cu-loaded rare-earth hydrides (Cu/REH2) work as effective catalysts for methanol synthesis from CO and H2 at temps. below 100°C, where the conventional Cu/ZnO/Al2O3 industrial catalyst does not work well. This catalytic activity is due to neg. charged Cu sites that originate from the highly electron-donating support material and hydride ions directly reactive with CO. The activation energy and turn over frequency for the catalyst are less than half and ~ 20 times higher than that for conventional Cu-based catalysts, resp. The present work demonstrates that anionic electrons with a low work function, the metallic nature of the support material, and hydride ions in the support play key roles for low-temp. methanol synthesis.
- 29Stangeland, K.; Li, H.; Yu, Z. Thermodynamic Analysis of Chemical and Phase Equilibria in CO2 Hydrogenation to Methanol, Dimethyl Ether, and Higher Alcohols. Ind. Eng. Chem. Res. 2018, 57 (11), 4081– 4094, DOI: 10.1021/acs.iecr.7b0486629https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjs1KjtL8%253D&md5=a9da8b9b3a6862f37a25b9160cc60806Thermodynamic Analysis of Chemical and Phase Equilibria in CO2 Hydrogenation to Methanol, Dimethyl Ether, and Higher AlcoholsStangeland, Kristian; Li, Hailong; Yu, ZhixinIndustrial & Engineering Chemistry Research (2018), 57 (11), 4081-4094CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)CO2 hydrogenation can lead to the formation of various products, of which methanol, di-Me ether (DME) and ethanol have received great attention. In this study, a comprehensive thermodn. anal. of CO2 hydrogenation in binary (methanol/CO) and ternary product systems (methanol/CO with DME or ethanol) is conducted in Aspen Plus by the Gibbs free energy minimization method combined with phase equil. calcns. Product condensation can be utilized to circumvent thermodn. restrictions on product yield. Significant improvements in CO2 conversion can be achieved by operating at conditions favorable for product condensation, whereas the selectivity is mildly affected. The relevance of the results herein is discussed with regards to recent advances in catalysis and process design for CO2 hydrogenation. Our study highlights the importance of obtaining a thorough understanding of the thermodn. of CO2 hydrogenation processes, which will be crit. for developing potential breakthrough technol. applicable at the industrial scale.
Supporting Information
Supporting Information
The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.2c13801.
XRD patterns for the Pd–Mo catalyst and the previously reported PdMo intermetallic, FFT of a single h-PdMo particle, N2-TPD profiles for h-PdMo and Mo2N, XRD patterns for the h-PdMo catalyst before and after TPD measurements, XRD patterns for the h-PdMo/Mo2N and Pd/Mo2N catalysts, high-resolution TEM images of h-PdMo/Mo2N and Pd/Mo2N, FFT of a single h-PdMo nanoparticle and Pd nanoparticle on Mo2N, reproducibility test of h-PdMo/Mo2N catalyst, H2-TPR profile for the h-PdMo/Mo2N catalyst, XRD patterns and methanol synthesis activity of h-PdMo/Mo2N catalyst synthesized by using Pd(NH3)4Cl2·H2O as a Pd source, catalytic activity over Mo2N and h-PdMo catalysts under ambient pressure, comparison of catalytic activity over h-PdMo/Mo2N and Cu/ZnO/Al2O3 catalysts, CO2 hydrogenation with different flow rates, pressure dependence of catalytic activity over the h-PdMo catalyst, GC-MS spectrum of 13CH3OH obtained from 13CO2, catalytic activity and activation energy over the h-PdMo/Mo2N and h-PdMo catalysts under pressurized conditions, XRD patterns for the h-PdMo catalyst before and after methanol synthesis, CO-TPD profiles for h-PdMo and Pd, DRIFT spectra over the h-PdMo catalyst, CO hydrogenation to methanol over the h-PdMo/Mo2N catalyst under atmospheric pressure, synthesis rate of byproducts and product distribution during CO2 hydrogenation, and tables for compositional analysis, structural properties of the studied catalysts, activation energies over various Pd-based catalysts, comparison of TOFs over different catalysts, and CO2 conversion over the h-PdMo/Mo2N catalyst (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.