Superabsorbent polymers (SAPs) are important in the health-care and personal care industries. Products like bed pads and diapers improve the comfort and sanitary conditions for people all over the world, with SAPs reaching yearly production volumes of ca. 2 million tons. However, recent sustainability issues have questioned the high negative footprint of polymers from nonrenewable resources. Biomacromolecules, especially when functionalized, have properties that make them an attractive alternative for the production of biobased SAPs. Proteins are a particularly interesting alternative due to their high variability and because of their relatively low price, being available as side streams from the agricultural industries. Due to the harsh extraction conditions, these side stream proteins are not competing with the food industry and alternative source-effective uses are advantageous in a circular bioeconomy. As the properties of a SAP material come from a combination of neutralized functional groups to promote polar liquid uptake and intermolecular cross-links to prevent dissolution, proteins offer unique opportunities due to their variability in polymerization. An increased understanding of the protein characteristics and how these can be tuned through functionalization is therefore a prerequisite for the successful development of a commercial biobased SAP that utilizes industrial and nontoxic wastes toward more sustainable products. This review focuses on proteins as biomacromolecules with relevant characteristics for superabsorbent functions, and discusses the opportunities that they may offer toward sustainable SAPs utilizing nontoxic chemicals and following the green chemistry principles.

Nowadays, one of the most challenging sustainability issues faced by society is the safety of water resources. Water pollution caused by hazardous contaminants (e.g., heavy metal ions, emerging contaminants, organic dyes) is a serious issue because of acute toxicities and the carcinogenic nature of the pollutants. With the advent of materials engineering, unprecedented technical advances have been achieved through diverse technologies in recent decades, including photocatalytic oxidation, photo-Fenton, electron Fenton, adsorption, and separation. However, the applications of these technologies have suffered from several limitations, such as the uncompleted degradation efficiency, high energy consumption, narrow pH range for application etc. Metal–organic frameworks (MOFs) have aroused increasing studies in gas storage, separation, sensing, water/air purification, and catalysis. The effectiveness of the above applications has been extensively recognized. In recent years, these highly ordered and porous crystalline structures have been recognized as a potential alternative to overcome the technical limitations in the area of water pollution control. This perspective article reports recent progress in the applications of MOFs in the field of environmental pollutant elimination, including the adsorption, advanced oxidation process (AOP) heterogeneous Fenton-like reactions, and MOF-based membranes for pollutant filtration.

Current energy shortages and environmental crises have compelled researchers to look for inexpensive and sustainable resources that can be obtained via environmentally friendly routes to produce novel functional materials. Biomass has been identified as one of the promising candidates given its availability in large quantities and renewable nature. Among the various feasible synthetic strategies, hydrothermal carbonization (HTC) has been admired for its energy efficiency and ability to synthesize carbonaceous materials for use in a wide range of applications. In this review, the different types of biomass and strategies available for the synthesis of carbon-based materials are discussed. Furthermore, factors influencing the efficiency of each strategy are analyzed and evaluated. Subsequently, the utilization of carbonaceous materials in environmental, catalytic, electrical, and biological applications are reviewed to further demonstrate their functionalities across different fields.

The research on solution processed metal halide perovskite solar cells (PSCs) as a new type of solar cells has experienced explosive growth since the first report in 2009. It is impressive that solar energy conversion efficiency has increased to over 23%. Outstanding optoelectronic properties including high absorption coefficient, high mobility, and long diffusion length of charge carriers have been revealed in the family of hybrid organic inorganic halide perovskite materials that are considered the heart of solar cells. A long-anticipated feature for solar cells that the diffusion lengths of charge carriers outstrip the active layer thickness of a device has been demonstrated in PSCs so that the efficiency of extracting photocarriers, particularly electrons at the interfaces becomes a key parameter controlling global device performance. The n-type semiconductor TiO₂ with the merits of thermal and chemical stability, low cost, and suitable band edge positions has been regarded an ideal electron transporting layer (ETL) material in PSCs performing the function of selectively extracting photoelectrons and subsequently delivering them toward a current collector. Besides the highly concerning energy conversion efficiency of PSCs, the challenge of the current–voltage hysteresis phenomenon and instability of PSCs are also revealed to be closely related with TiO₂ ETLs. In this review, the recent progress on strategies for modifying TiO₂ ETLs by controlling morphology, surface modification, doping, and constructing composites to improve global performance of PSCs is reviewed. Moreover, the perspective on future development of TiO₂ based ETLs for high performance PSCs is proposed on the basis of the comprehensive and deep understanding of TiO₂ from the area of photocatalysis. It is anticipated that finely tailoring the features and properties of TiO₂ ETLs will further release large room for exciting enhancements in the global performance of PSCs.

Lithium ion-conducting metal–organic frameworks (MOFs) are rapidly gaining interest because of their potential application as ion-permeable, robust electrode separators in rechargeable batteries, arguably the most ubiquitous portable clean energy storage devices developed to date. A novel, water-stable 2D sheet-like neutral Cu(I)–sulfonate MOF featuring π-acidic naphthalenediimide (NDI) ligands that can simultaneously bind guest lithium ions with its carbonyl and uncoordinated sulfonate oxygen atoms and charge diffuse perchlorate anions through anion−π interaction has been constructed. While the pristine MOF pellets displayed poor intrinsic electrical conductivity (4.65 × 10^–10 S/m) at room temperature due to inadequate charge carrier density and electron delocalization pathway, upon infiltration of LiClO₄, its ionic conductivity surged almost million times to 2.3 × 10^–4 S/m, and the activation energy for charge carrier transport dropped to a mere 0.167 eV. In contrast, the conductivity of Bu₄NClO₄-treated MOF remained practically unchanged from its original value possibly due to size exclusion and/or facile removal of large uncoordinated Bu₄N⁺ cations, revealing the positive impact of Li⁺ ion infiltration and binding. Thus, this report presents a rare, if not the first, example of significant lithium ion conductivity of a neutral, practically solvent-free, not post-synthetically modified MOF and offers a new strategy to develop ion-conducting sulfonate MOFs for potential battery applications.

CoP is a promising catalyst material to replace noble metals in water electrolysis. To further explore the potential of CoP in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), we utilize vertical graphene nanohills (VGNHs) that are known to enhance catalytic performances through superaerophobicity. Unique CoP chrysanthemum-like structures are formed on VGNHs through a facile, one-step electrodeposition reaction. Because of the highly conductive VGNH support and the modified CoP nanostructures, the optimized CoP/VGNHs hybrid catalyst exhibits excellent electrocatalytic activities toward HER in 0.5 M H₂SO₄, such as a low overpotential at 10 mA cm^–2 (η₁₀) of 51 mV, a small Tafel slope of 36 mV dec^–1, and a long-term stability. Specifically, the overpotential at 100 mA cm^–2 (η₁₀₀) is merely 125 mV, an outstanding performance for a noble metal-free catalyst. Furthermore, the HER performance in 1.0 M KOH (η₁₀ of 93 mV) and the OER performance in the same alkaline medium (η₁₀ of 300 mV) are highly competitive, making CoP/VGNHs also an excellent bifunctional electrocatalyst yielding a current density of 10 mA cm^–2 at a low voltage of 1.63 V. This novel nanostructure offers an efficient strategy for the development of nonprecious metal catalysts for water electrolysis.

Acid catalysts derived from a well-known reaction of 1-methylimidazole and chlorosulfonic acid system are considered very important, but sufficient details are lacking on their structure information. We studied and report the structural characterization of products from a reaction of 1-methylimidazole and chlorosulfonic acid. Our results from crystallography, nuclear magnetic resonance spectroscopy (NMR), elemental analysis, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) indicate the formation of a unique reaction mixture of zwitterion-type salt [C₁im-SO₃] and ionic liquid [C₁im-SO₃H]Cl at a 7:3 ratio instead of only ionic liquids as proposed by others.

The molasses embedded hybrid coal (Hybrid Coal by Korea Institute of Energy Research; HCK) was previously proposed as an attractive alternative to low-rank coals that tend to show low calorific values and high CO₂ emissions. HCK was synthesized by mixing molasses with a low-rank coal to enhance its heating value. Nevertheless, food ethics regarding molasses additives still have impeded its commercial acceptance. In this study, we propose a glycerol (nonfood)-based coal upgrading process to improve the combustion kinetics and heating value of hybrid coal in comparison to the previous HCK. The process involves drying at 105 °C followed by torrefaction process at 250 °C. During torrefaction, the glycerol additive starts to evaporate at about 180 °C and then is almost vaporized out to the coal surface. To avoid glycerol loss, we employ sulfuric acid as a torrefaction catalyst to suppress glycerol evaporation. In comparison to the molasses yield of 65% after torrefaction in the previous HCK synthesis process, glycerol-embedded torrefaction with sulfuric acid showed a 55% yield in mass. The glycerol-embedded hybrid coal shows a homogeneous combustion peak regardless of the mixing ratios, leading to a 35% reduction of unburned carbon emissions, which is one of the particular matter sources of combustion flue gas. Furthermore, the proposed synthesis process increases the net caloric value to 80% and lowers the water uptake to 84%, even without a higher SO₂ emission, in comparison with raw coal.

A new, sustainable catalytic route for the synthesis of tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), a compound with potential application in polymer industry, is presented starting from the bio-based platform chemical 5-(hydroxymethyl)furfural (HMF). This conversion was successfully achieved via oxidation of tetrahydrofuran-2,5-dimethanol (THFDM) over hydrotalcite (HT)-supported gold nanoparticle catalysts (∼2 wt %) in water. THFDM was readily obtained with high yield (>99%) from HMF at a demonstrated 20 g scale by catalytic hydrogenation. The highest yield of THFDCA (91%) was achieved after 7 h at 110 °C under 30 bar air pressure and without addition of a homogeneous base. Additionally, Au–Cu bimetallic catalysts supported on HT were prepared and showed enhanced activity at lower temperature compared to the monometallic gold catalysts. In addition to THFDCA, the intermediate oxidation product with one alcohol and one carboxylic acid group (5-hydroxymethyl tetrahydrofuran-2-carboxylic acid, THFCA) was identified and isolated from the reactions. Further investigations indicated that the gold nanoparticle size and basicity of HT supports significantly influence the performance of the catalyst and that sintering of gold nanoparticles was the main pathway for catalyst deactivation. Operation in a continuous setup using one of the Au–Cu catalysts revealed that product adsorption and deposition also contributes to a decrease in catalyst performance.

Atomic interface engineering can endow electrode materials with fascinating properties by tailoring their physicochemical behaviors, which will unlock great potential for achieving high-performance lithium storage. Herein, a newfangled concept of presenting an interfacial electric field and atomic disorder in Co_0.85Se by interface engineering is demonstrated for realizing its high-rate and large-capacity lithium storage. Transmission electron microscopy confirms the formation of abundant atomic interfaces between Co_0.85Se and N-doped carbon (NC), and meanwhile, X-ray absorption near-edge structure tests disclose the negative charge shifts from Co_0.85Se to NC as well as the existence of disordered Co/Se atoms and/or dangling bonds in the interface region. On one hand, the lopsided charge distribution around the atomic interface can induce an interfacial electric field, which will afford a foreign Coulomb force to facilitate the Li⁺ transmission, thus greatly improving high-rate capability. On the other hand, the disordered Co/Se atoms and/or dangling bonds in the interface region could act as the extra active sites to hold the lithium for increasing the specific capacity. Benefiting from this multiscale coordination regulation, Co_0.85Se/NC displays high discharge specific capacity (1139 mA h g^–1 at 0.1 A g^–1), large initial Coulombic efficiency (87.9%), and excellent rate performance. This work presents a new perspective for an in-depth understanding of the atomic interface–performance relationship of Co_0.85Se/NC, and meanwhile, this concept can be used for guiding the design of other energy-related electrode materials.

Lignin, which is biosynthesized through oxidative radical polymerization from primary monolignols during plant growth, represents the most abundant source of renewable aromatic resources. The search for efficient and selective catalysts for the production of monolignols and their corresponding unsaturated derivatives from the direct depolymerization of lignin is of great interest and importance, as such products are important platform chemicals for the synthesis of natural products, pharmaceuticals, and functional materials. We report herein the first case of a supported molybdenum catalyst that functions as an efficient and selective catalyst for the fragmentation of woody lignocelluloses, leading to monolignols and ethers in high yields with high selectivity. Hydrogenation of the side chain and recondensation were not observed, suggesting that etherification acts as a new stabilization mechanism in the current Mo catalytic system. The (hemi)cellulose components were well preserved and amenable to valorization via enzymatic hydrolysis and chemocatalytic conversion. This method constitutes an economically responsible pathway for lignin valorization as well as fractionation and sequential utilization of all of the biomass components.

Polymerized ionic liquids (PILs) have several advantages over ionic liquids, such as easy handling, good electrochemical performance, and chemical compatibility. In this research, a solid-state electrolyte composite membrane was successfully fabricated by using an imidazolium-based polymerized ionic liquid as polymer matrix, a kind of porous fiber cloth as rigid frame, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as lithium salt. The ionic conductivity of the composite electrolyte with 2.0 mol/kg LiTFSI is 7.78 × 10^–5 S cm^–1 at 30 °C and reaches 5.92 × 10^–4 S cm^–1 at 60 °C, which is considered a satisfactory value for potential application in lithium-ion batteries. The specific discharge capacity of the LiFePO₄/Li cell with as-prepared composite electrolyte is 138.4 mAh g^–1, and 90% of the discharge capacity is retained after 250 cycles at 60 °C. In order to further improve the conductivity, Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) ceramic electrolyte particles are dispersed in a PIL polymer matrix to prepare the PIL-LiTFSI-LATP composite electrolyte. LiFePO₄/Li cells using PIL-LiTFSI-LATP (10 wt % LATP) as a solid-state electrolyte exhibit excellent rate performance and high capacity retention (close to 97% after 250 cycles at 60 °C). This work may provide a unique way to prepare a new series of electrolytes for high-performance solid-state lithium batteries.

In this work, natural sediment was used as an alternative and green inorganic source to synthesize valuable structured Al-MCM-41 material by a hydrothermal process. This intertidal sediment contains a mixture of clay minerals (montmorillonite and ilite) and minerals (quartz and feldspar) providing large SiO₂ (∼64%) and Al₂O₃ (∼15%) content which were efficiently extracted by alkaline fusion. The synthesized mesoporous material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance infrared Fourier transform spectroscopy (FT-IR), N₂ physisorption, and ²⁷Al solid-state magic angle spinning nuclear magnetic resonance spectroscopy (²⁷Al MAS NMR). The results achieved reveal that pure and highly ordered hexagonal mesoporous aluminosilicate MCM-41 containing structural aluminum has been successfully synthesized. Moreover, it was evidenced that the obtained solid presents uniform pore size distribution (3.6 Å) as well as high pore volume (0.59 cm³g^–1) and elevated specific surface area (807 m²g^–1).

The synthesis of amines from biomass-based feedstock is in high demand given the depletion of fossil fuels. Reductive amination is one of the most straightforward synthetic methods to obtain a variety of amines; however, it is prone to denaturation and side reactions under the harsh conditions required. By fine-tuning the surface acidity of niobic acid (Nb₂O₅·nH₂O), we evaluated the relationship between catalytic activity on reductive amination with the amount of acid sites on Nb₂O₅·nH₂O. Ru/Nb₂O₅·nH₂O reduced at 300 °C was found to be an efficient catalyst for the reductive amination of biomass-derived carbonyl compounds under low temperature to afford primary amines, without the formation of secondary amines or hydrogenated products.

Organosilicon compounds, because of their unique properties, are widely used in a variety of organic processes, and thus the constant improvement of current methods is still needed. We present slurry-phase hydrosilylation reactions using novel supported ionic liquid-phase (SILP) catalysts containing rhodium complexes immobilized in four phosphonium ionic liquids (ILs) on silica support. The obtained new SILP catalysts were analyzed by infrared technique, low-temperature nitrogen physisorption at 77 K, and scanning electronic microscopy with energy-dispersive X-ray spectroscopy to provide structural information on these materials. Moreover, the catalytic activity in hydrosilylation reactions was evaluated and compared with the catalytic activity of rhodium catalysts dissolved in the same ILs when using a biphasic reaction system (IL/catalyst as one phase and mixture of substrates as a second phase). The rhodium-based SILP catalysts proved to be much more efficient than when used in a biphasic system composed of a similar catalyst and reactants. Furthermore, as a result of the presented study, we have identified a highly active SILP catalyst ([{Rh(μ-OSiMe₃)(cod)}₂]/[P₆₆₆₁₄][NTf₂] supported on silica) that allowed us to decrease the amount of catalyst used in the reaction by 1000 times in comparison with the amount of catalyst required while performing reaction using the biphasic catalytic system. The proposed method of utilization of SILP materials can become a significant step in reducing expensive organometallic catalyst consumption in organic chemistry and, when applied more broadly, lead to significant cost savings, eventually making the production of many organic molecules more sustainable.

Chemical transformation of shale gas components under mild conditions is ideal for utilizing the shale gas resource to produce high-value intermediates of chemical industries and fuel feedstocks of energy industries. Here we report that single Rh atom sites, Rh₁O₅ anchored in micropores of HZSM-5, can catalyze oxidation of ethane by hydrogen peroxide in aqueous solution to form acetic acid and formic acid at a temperature ≤ 50 °C at a pressure of ethane at 1.5 bar. Conversion of 1.5 bar of ethane to carboxylic acids at 50 °C in a Parr rector reaches 37% within 2 h. Acetic acid and formic acid are formed through two parallel reaction pathways with apparent activation barriers of 32.5 and 35.5 kJ/mol in the temperature range of 50–72 °C, respectively. Turnover rates for forming carboxylic acids are 0.060 acetic acid molecules on each Rh₁O₅ site per second (216 mol of acetic acid per mol Rh per hour) and 0.127 formic acid molecules on each Rh₁O₅ site per second (457 mol of formic acid per mol of Rh per hour) at 50 °C. This study suggests a very promising catalytic process of synthesis of carboxylic acids at near room temperature at ambient pressure.

The use of biomass porous carbon materials for energy storage has attracted tremendous attention in current research and has great applications in supercapacitors, lithium batteries, and fuel cells. In this work, sisal-derived activated carbon fibers (SC) are obtained through a simple and convenient method using sisal, a natural biomass material, as a precursor. SC-750 has a high specific surface area (S_BET: 2289 m² g^–1) and an optimized pore size distribution with a total pore volume of 1.23 cm³ g^–1. For supercapacitors, the obtained SC-750 exhibits excellent specific capacitance and cycle stability. The specific capacitance value is 415 F g^–1 at 0.5 A g^–1, and SC-750 shows a 93% capacitance retention after a long cycle (10,000 cycles) at 10 A g^–1. In addition, the SC-750-based symmetric supercapacitor exhibits a high energy density of 11.9 Wh kg^–1 in 6 M KOH electrolyte. Therefore, the results of this work demonstrate that sisal-derived activated carbon fiber has a great application value in supercapacitors.

Mediterranean climate areas are home to highly relevant and distinctive agro-ecosystems, where sustainability is threatened by water scarcity and continuous loss of soil organic carbon. In these systems, recycling strategies to close the loop between crop production (and agro-related industries) and soil conservation are of special interest in the current context of climate change mitigation. Pyrolysis represents a recycling option for the production of energy and biochar, a carbonaceous product with a wide range of environmental and agronomic applications. Considering that biochar functionality depends on both the original biomass and the pyrolysis conditions, we produced and characterized 22 biochars in order to evaluate their potential to sequester C and modify soil physicochemical properties. The pore size distribution was a function of the original biomass and did not change with the temperature of pyrolysis. The highest number of pores within the size 0.2–30 μm, relevant for plant available water retention, was reached at 600 °C. However, ideal pyrolysis conditions to optimize C stability and hydrologic properties was reached at 400 °C in woody derived biochars, as higher temperatures lead to a nontransient hydrophobicity. This study highlights relevant physicochemical properties of locally derived biochars that can be used to tackle specific challenges in Mediterranean agroecosystems.

The development of biodegradable packaging films can resolve environmental issues caused by plastic waste, but it still remains a great challenge to develop economically feasible polymers that simultaneously balance robust mechanical properties, biodegradability, and transparency. In this work, we describe the bench-scale synthesis (∼1.5 kg) and blown film characterization of new biodegradable aliphatic–aromatic copolymers, poly(1,4-butylene-1,4-cyclohexanedimethylene carbonate–terephthalate)s (PBCCTs) with different molar ratios of two diol monomers, 1,4-cyclohexanedimethanol (CHDM) and 1,4-butandiol (BD), from 0:1 to 5:5 (CHDM/BD) to optimize the mechanical, optical, and thermal properties and biodegradability. The incorporation of CHDM units significantly impacted the thermal properties of the blown films from these copolymers; PBCCT films with 50 mol % CHDM content had a more amorphous and glassy character compared with the films with 0 mol % CHDM. And, PBCCT films with 30–50% CHDM content exhibited superior mechanical properties (tear strength = 11.5 kgf/mm and tensile strength = 369 kgf/cm²) and comparable transparency (haze = 16%) to those of nondegradable polyethylenes (PEs), the most commonly employed materials for packaging film applications. Taken together, the bench-scale synthesis of biodegradable polymers with suitable thermomechanical, optical, and permeability properties presented here showcases the potential of these materials as sustainable packaging materials.

Biorefractory humic substances (HS) that are ubiquitously present in nitrogen-rich wastewater streams, such as landfill leachate and livestock waste after anaerobic digestion, can potentially impact nitritation–anammox processes. In this study, multiple sequencing methods (e.g., 16S rRNA sequencing, clone library analysis, and metagenome sequencing) were employed to reveal the response of nitrosifying microbiota to HS at various concentrations (0–50 mg/L). Long-term reactor operation revealed that the nitrite yield was overall stable during all of the experimental days; however, fluctuations were observed as a result of sudden HS loads. The characterization by 16S rRNA sequencing indicated a decreased abundance of the phylum Proteobacteria (from 90.8% in HS0 to 52.1% in HS50) and an increased abundance of the phylum Bacteroidetes (from 4.7% in HS0 to 35.3% in HS50) upon exposure to HS. Both 16S rRNA sequencing and metagenome sequencing revealed that the family Nitrosomonadaceae, which was dominated by the genus Nitrosomonas, dramatically decreased, i.e., from ca. 70% in HS0 to ca. 40% in HS50. Both amoA-based clone libraries and metagenome sequencing suggested a substantial shift of AOB species, e.g., the emergence and enrichment of Nitrosomonas mobiliz upon exposure to HS. Interestingly, the amoABC gene was initially inhibited by 5 mg/L HS and then recovered at a higher level of HS (50 mg/L). In comparison, levels of hao gene were reduced with increasing HS (0, 5, and 50 mg/L). In addition, the abundance of genes assigned to membrane transport decreased after the addition of HS, and this reduction was likely associated with the electron shuttle roles of HS. Overall, the findings of this study provide insights into the response of core species and key genes to HS in nitritation systems.

Pyrolytic lignin is the collective name of the lignin-derived fraction of pyrolysis liquids. Conversion of this fraction to biobased chemicals is considered an attractive valorization route. Here we report experimental studies on the ozonation of a pine-derived pyrolytic lignin dissolved in methanol (33 wt %). Results show a high reactivity of ozone, and a molecular weight reduction of up to 40% was obtained under mild conditions (0 °C, atmospheric pressure) without the need for catalysts. Detailed analysis of the product mixtures (GC/MS-FID, HPLC, GPC, NMR) showed the presence of low molecular weight (di)acids and esters, along with larger highly oxygenated aliphatics. A reaction network is proposed including the heterolytic cleavage of aromatic rings, followed by secondary reactions. The observations were supported by experimental studies using representative pyrolytic lignin model compounds and a biosynthetic lignin oligomer, which aided further elucidation on the reactivity trends for different chemical functionalities. Accordingly, the presence of hydroxy and methoxy substituents on the aromatic rings is shown to be the main reason for the high reactivity of pyrolytic lignin upon ozone exposure.

There have been extensive demands for eco-friendly, lightweight, flexible, and high performance supercapacitors for advanced applications like wearable electronics, hybrid electric vehicles, and industrial grid storage. In this work, a metalless nanocellulose-based PANI/RGO electrode with excellent flexibility, mechanical strength, and conductivity was developed and assembled into sandwich-like supercapacitors. Reduced graphene oxide (RGO) was mixed into aniline during the in situ polymerization of PANI to improve conductivity of the composite electrode. This eco-friendly metalless nanocellulose based electrode was fabricated via filtrations driven by a vacuum and assembled into sandwich structures. The ratios between nanocellulose, PANI, and RGO were optimized to achieve both high electrochemical performance and good mechanical properties. The composite electrode has a large active materials mass loading ratio of 16.5 mg/cm², and the assembled supercapacitor gives small impedance at 3.90 Ω, suggesting an excellent conductivity. This work shows the great potential of developed flexible and lightweight nanocellulose composites in the fabrication of supercapacitors that can be used in a variety of biomedical applications including e-skins.

Urea electrolysis is a promising route to utilize urea-rich wastewater as an energy source to produce hydrogen on the cathode or generate electricity through a direct urea fuel cell, which offers great potential for simultaneous water remediation and energy recovery. Here, we report a scalable synthetic strategy to prepare NiCo layer double hydroxide (NiCo LDH) as an efficient catalyst for urea electrooxidation. NiCo LDH with NO₃^– intercalant exhibited the best electrocatalytic performance and selectivity toward urea oxidation with a low onset potential, high faradaic efficiency, and high durability. The interlayer spacing in the LDH structure was found to play a pivotal role in the urea oxidation electrocatalysis with higher activity/selectivity under larger spacings. Further analysis of the urea oxidation product could potentially enable selective urine treatment into environmentalally friendly products.

Overall water splitting is an attractive technology to produce clean hydrogen and oxygen. In this study, we constructed amorphous Ni_xCo_y layered double hydroxide (LDH) hybridized with three-dimensional NiCo₂O₄ to fabricate a core–shell nanowire array on Ni foam (NiCo₂O₄@Ni_xCo_y LDH/NF) as a highly efficient electrocatalyst for overall water electrolysis. By tuning the Ni/Co molar ratio in Ni_xCo_y LDH, extremely low overpotentials of 193 mV for oxygen evolution reaction (OER) and 115 mV for hydrogen evolution reaction (HER) at a current density of 10 mA cm^–2 can be achieved for the NiCo₂O₄@Ni_0.796Co LDH/NF. Detailed investigations verify that the hybrid structure can increase intrinsic activity of the NiCo₂O₄@Ni_0.796Co LDH/NF and enhance the charge-transfer rate. Moreover, a strong electronic interaction between the heterogeneous elements Ni and Co at the interface of the NiCo₂O₄ and Ni_xCo_y LDH might ultimately influence the catalytic performance.

In the terrestrial biosphere, biomass deconstruction is conducted by microbes employing a variety of complementary strategies, many of which remain to be discovered. Moreover, the biofuels industry seeks more efficient (and less costly) cellulase formulations upon which to launch the nascent sustainable bioenergy economy. The glycan decoration of fungal cellulases has been shown to protect these enzymes from protease action and to enhance binding to cellulose. We show here that thermal tolerant bacterial cellulases are glycosylated as well, although the types and extents of decoration differ from their Eukaryotic counterparts. Our major findings are that glycosylation of CelA is uniform across its three linker peptides and composed of mainly galactose disaccharides (which is unique) and that this glycosylation dramatically impacts the hydrolysis of insoluble substrates, proteolytic and thermal stability, and substrate binding and changes the dynamics of the enzyme. This study suggests that the glycosylation of CelA is crucial for its exceptionally high cellulolytic activity on biomass and provides the robustness needed for this enzyme to function in harsh environments including industrial settings.

Herein, we have successfully designed two ecofriendly, biocompatible, and cost-effective devices, i.e., a piezoelectric nanogenerator (PENG) and a self-charged photo-power cell (PPC) by developing a multifunctional cetyltrimethylammonium bromide (CTAB) modified montmorillonite (MMT) incorporated poly(vinylidene fluoride) (PVDF) thin film with large electroactive β crystallites and dielectric properties. Incorporation of CTAB modified MMT in PVDF leads to nucleation of piezoelectric β crystallite (F(β)) ∼ 91% as well as the dielectric constant ∼48 at 3 mass % doping of CTAB-MMT. The enrichment of the electroactive β phase crystallization and high dielectric constant pilot to a good piezoelectricity (d₃₃) ∼ 62.5 pC/N at 50 Hz of the thin film. Our CTAB-MMT/PVDF based PENG (CMPENG) with superior piezoelectricity shows high output power generation with power density ∼ 50.72 mW/cm³ under periodic finger impartation and having the ability to charge a 1 μF capacitor up to 2.4 V within 14 s under gentle finger impartation. CMPENG also have the potential to glow up commercially available 26 blue light-emitting diodes (LEDs) connected in series. The self-charged PPC has been designed with the thin film in association with MnO₂-MWNT/PVP/H₃PO₄. Our PPC is able to generate supercilious output voltage ∼ 1.38 V and short circuit current ∼ 3.7 mA/cm²under light illumination with specific areal capacitance and energy storage efficiency of ∼1501 F/m² and ∼93%, respectively. The realistic application of our PPC is investigated by lighting 24 blue LEDs for 7 days with the same intensity by charging the device once for 50 s.

In this research article, use of bovine serum albumin, a protein with a free amine (−NH₂) functional group, is demonstrated for the preparation of protein-functionalized aerogel membranes (PFAMs) utilizing naturally occurring genipin as a cross-linking agent. PFAMs were characterized using SEM, FT-IR, solid-UV, and TGA. PFAMs are highly stable and recyclable under aqueous conditions and were successfully tested for efficient separation of an oil spill as well as an emulsion under gravity-driven force. PFAMs produced ∼98% pure water with a high flux rate ranging from 430 to 605 L·m^–2·h^–1 for lab-scale separations under gravity. PFAMs were tested for their biodegradability under soil conditions. This work is one of the best examples for the development of environmentally friendly porous membranes using abundant seaweed biomass through cross-linking chemistry of proteins.

TiO₂ is an important inorganic material which is commercially produced by either the chloride or the sulfate process. In general, the latter has lower cost and a lower entry barrier than the former. However, the environmental impact associated with the sulfate process is more visible than the chloride process because the sulfuric acid with a low concentration (∼20 wt %) cannot be cost-effectively recycled; therefore, it has to be neutralized, generating a large amount of wet and useless red gypsum (RG). In this research, a potentially more ecofriendly chemical pathway for TiO₂ production from concentrated titanium ore, aka titania slag, is presented. The new method consists of three critical steps including transformation of the titania slag to a lower-valence titanium suboxide by aluminothermic reduction, digestion by using mild acid, and controlled hydrolysis accompanied by acid recycling. As a result of the phase transformation, the digestion of titanium from the titanium feedstock becomes easier such that it is feasible to use relatively mild acid to replace concentrated acid, reducing the environmental impact from the red gypsum because the need for neutralizing the waste acid can be eliminated. High-purity hydrous TiO₂ can be prepared after hydrolysis, and the spent liquor can be effectively recycled back to the digestion unit.

Achieving highly selective and efficient reduction of carbon dioxide into methane will significantly affect the resolution of two of the current crucial issues facing humanity, namely environmental problems due to excess CO₂ and the increasing demand for clean energy. In this paper, the thermochemical reduction of carbon dioxide into methane by the activated alkaline-earth metal hydrides was reported. The results of the correlational experiments show that the reduction of carbon dioxide by the activated nanosized alkaline-earth metal hydrides is highly selective and efficient in the absence of a catalyst under moderate conditions. Only a hydrocarbon species, namely methane, is produced, and the methane yield can reach 88% for the reactions between CaH₂ and carbon dioxide. The mole percentage and yield of CH₄ in the gas-state products depend largely on the type of alkaline-earth metal hydride, reaction temperature, and reaction time.

Economic biofuel production requires high sugar yields during biomass pretreatment, however, the chemical and structural features of biomass can be obstructive toward efficient xylose hydrolysis. Here, we tested the hindrance imposed by the multiscale structure of biomass on the hydrolysis of xylan during dilute acid pretreatment by studying the effects of both the chemical nature of xylan and physical structure of biomass. Dilute acid pretreatment of poplar wood at particle sizes ranging from 10 μm to 10 mm was conducted, however, no significant differences in the rates of xylan hydrolysis were observed over more than 2 orders of magnitude in particle size. A significant reduction in the rate of xylan hydrolysis was observed when compared to the intrinsic rate of hydrolysis for isolated xylan. Thus, it appears likely that the chemical structure of xylan and/or the interaction of xylan with other polymers in the cell wall matrix have greater effects on xylan hydrolysis rates than mass transfer limitations.

This study tailored a novel engineered biochar as a solid catalyst for glucose isomerization by pyrolyzing Sn-functionalized wood waste under varying hypothesis-driven selected conditions (i.e., 650, 750, and 850 °C in N₂ and CO₂ atmosphere). The results showed that properties of biochar support (e.g., porosity and acid/base property) and chemical speciation of Sn were highly related to their catalytic performance. Variations in pyrolysis temperature and feed gas modified the porous structure and surface functionality of biochar as well as the valence state of doped Sn on the biochar. For the N₂ biochars, higher pyrolysis temperature enhanced the fructose yield yet had trivial effect on the selectivity, where 12.1 mol % fructose can be obtained at 150 °C and 20 min using biochar produced at 850 °C. This was plausibly attributed to the increased fraction of amorphous Sn structures and metallic Sn that were more reactive than its oxide form. At the pyrolysis temperature of 750 °C, the use of CO₂ increased the surface area by 40%, enlarged the pore volume from 0.062 to 0.107 cm³ g^–1, and enriched the amorphous Sn structures compared to those for N₂ biochar. This probably accounted for the better catalytic performance of CO₂ biochar than that of N₂ biochar (∼50% and 100% enhancement in fructose yield and selectivity, respectively). The Sn-biochar catalysts may have promoted glucose isomerization via both the Lewis acid and Brønsted base pathways. This study paves a new way to design biochar as a sustainable and low-cost solid catalyst for biorefinery applications.

Rechargeable aluminum-ion batteries are considered promising candidates for the new generation of energy storage systems because of their high capacity, low cost, and high security. The most urgent challenge to be addressed for the practical application of aluminum-ion batteries is exploring cathode materials with simple fabrication processes and preeminent electrochemical performance. Herein, a flexible free-standing MoS₂/carbon nanofibers composite has been successfully synthesized by electrospinning and annealing treatment and investigated as a cathode material for rechargeable aluminum-ion batteries, delivering an initial discharge capacity of 293.2 mA h g^–1 at a current density of 100 mA g^–1 and maintaining 126.6 mA h g^–1 after 200 cycles. The novel free-standing MoS₂/carbon nanofibers composite can provide new ideas for the use of transition-metal sulfides as cathode materials for aluminum storage and facilitate the commercial adoption of aluminum-ion batteries.

A series of visible-light-active NH₂-MIL-125/TiO₂/CdS yolk–shell and hollow H-TiO₂/CdS hybrid heterostructures were successfully synthesized via the hydrolysis of NH₂-MIL-125 metal–organic framework (MOF) using thioacetamide (CH₃CSNH₂) and cadmium acetate (Cd (CH₃COO)₂·2H₂O) by the post solvothermal method, after which the obtained heterostructures were applied to H₂ photocatalytic production. Among the yolk–shell and hollow heterostructures, NH₂-MIL-125/TiO₂/CdS (30) and H-TiO₂/CdS (30) exhibited the highest H₂ production activity of 2997.482 and 1970. 813 μmol g^–1 h^–1, with the apparent quantum efficiency of 4.81% and 2.41% at 420 nm, respectively. These superior photocatalytic performances of the heterostructures could be due to the strong interaction of the component based on intimate contact, large surface area, and porous structures that assisted the mass transfer, thereby forming abundant reactive sites. Moreover, the introduction of CdS nanoparticles into the MOF derivatives enhanced the visible light absorption and improved the separation of electron–hole pairs via heterojunction with well-matched energy band gap. Furthermore, the H₂ production rate of the yolk–shell and hollow heterostructures were 18 and 12 times greater than the bare CdS. A probable mechanism was also proposed for the heterostructures. This work could open up new directions for the development of MOF-derived photocatalysts.

Accurate and precise control of the transition-metal ions in the docking sites of porous functional materials especially covalent-organic frameworks (COFs) is a challenging task in the synthesis of hybrid materials. In this work, we demonstrate the successful synthesis, characterization, and utilization of two stable vanadium docked COFs, namely VO-TAPT-2,3-DHTA and VO-PyTTA-2,3-DHTA as efficient heterogeneous catalysts for Mannich-type reactions. The obtained results revealed that the as-prepared vanadium-decorated COFs are robust and maintain framework crystallinity, reusability, and efficiency under the sway of electronic and steric effects. Significantly, this work opens up the opportunity for docking other metals and exploring practically and industrially important catalytic reactions.

Membrane separation is widely regarded as a promising technology for water treatment. To run the membrane at the optimal conditions, preheating of feedwater before being sent into the membrane unit is often employed, which results in high energy consumption. Here we report a multifunctional system that combines traditional pressure-driven membrane filtration with solar thermal technology based on a photothermal membrane for high-efficiency water treatment. The multifunctional membrane consists of multiwalled carbon nanotubes and polysulfone (MWCNT-PSf), which not only facilitates the water permeation through the membrane but also effectively heats the feed solution by sustainable solar energy. The composite membrane containing MWCNT demonstrates excellent light absorption of 94% over the full solar spectrum range, which can effectively preheat the feedwater. With the assistance of light irradiation, the MWCNT-PSf photothermal membrane exhibits high water flux over 314 L m^–2 h^–1 with a rejection above 95% for coomassie brilliant blue at 0.10 MPa, which is 101.3% higher than that without light irradiation. The solar-intensified ultrafiltration system based on a porous photothermal membrane provides a new avenue to treat wastewater or seawater.

Separating acetylene from light hydrocarbon mixtures like ethylene is a very important process for downstream industrial applications. Herein, we report a new MOF [CuL₂(SiF₆)] (UTSA-220, L = (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine) with dual functionalities featuring optimal pore size with strong binding sites for acetylene. UTSA-220 exhibits apparently higher uptake capacity for C₂H₂ than those for other light hydrocarbons. The potential of this material for trace C₂H₂ removal from C₂H₄ has also been demonstrated by a dynamic breakthrough experiment performed with C₂H₂/C₂H₄ (1/99 v/v) under simulated industrial conditions. According to the dispersion-corrected density functional theory (DFT-D) simulation, SiF₆^2– and azine moieties serve as preferential binding sites for C₂H₂, indicating the feasibility of the dual functionalities incorporated in UTSA-220 for adsorbent-based C₂H₂ separations.

Whereas transition-metal-catalyzed decarbonylative dehydration of fatty acids shows promise as a more sustainable route to α-olefins, the solvents used for this process have so far been toxic compounds such as N-methyl-2-pyrrolidone and 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone. Here, potential greener solvents are surveyed, using the well-defined precatalyst Pd(cinnamyl)Cl(DPEPhos) (1). In general, the superiority of aprotic and polar solvents for this process is striking. An analysis of the experimental observations and of mechanistic density functional theory calculations suggests that this superiority originates from the ability of polar solvents to stabilize the rate-determining transition state, located in the olefin-forming β-hydrogen transfer step. To create electronic and steric room for the transfer, a ligand must be dissociated. In polar solvents, the corresponding hydrogen acceptor (the anionic Brønsted base), dissociates, which facilitates the transfer. Conversely, in apolar solvents the bidentate phosphine ligand dissociates, which leads to a higher barrier. Importantly, the study identified γ-valerolactone, which can be obtained from biomass, as a solvent offering almost the same efficiency for the decarbonylative dehydration reaction as the traditional, toxic solvents. Other green solvents tend to either have too low boiling points (below the reaction temperature, 110°C) or to react with the substrate, the catalyst, or side products of the reaction.

Cellulose nanocrystals (CNCs) have great potentials in many applications, such as high-performance nanocomposites. However, there are many challenges in the industrial production of CNCs, such as high cost of acid recovery, acid disposal, low yield, and poor thermal stability. In this study, a simple process to extract CNCs via recyclable acid hydrolysis of microcrystalline cellulose (MCC) is presented. A high yield (up to 87.8%) of carboxylated CNCs was obtained using recyclable citric/hydrochloric acid mixtures compared to the 53.9% yield for sulfated CNCs via recyclable H₂SO₄ hydrolysis. The mild acid mixtures could be readily recovered and recycled three times and showed a slight effect on the size of CNCs, carboxyl content of citrate CNC surface, zeta potential value, and thermal stability. Both charged citrate CNCs and sulfate CNCs were excellent food Pickering emulsion stabilizers for soybean oil/water emulsion droplets, whose diameter decreased with increasing CNC contents. This work provides a simple and low-cost pathway to recover mineral or organic acids for the sustainable and green production of CNCs with high yield and thermal stability while addressing the environmental issue of acid disposal in large-scale production of CNCs.

The utilization of carbon dioxide in the synthesis of valuable chemicals has attained high attention in the last decades. Numerous new syntheses were developed by applying innovative catalysts and demonstrated the versatile application possibilities of the thermodynamic stable molecule. However, only a few reaction systems were developed into a technical application. In this work, we present investigations of a homogeneous catalyzed reaction system for the synthesis of formamides in a miniplant scale. The applied catalyst complex Ru-Macho was recycled via immobilization in a nonpolar alcohol phase and showed a high stability within the observed period of 234 h. The formed products were extracted in situ into an aqueous phase. An average yield of 48% N,N-dimethylformamide (DMF) proved a good activity of the reaction system. An alteration of the reaction designed into a two-step process allowed an extension of the product range to yield a broad variation of formamides with high yields up to 89%.

A series of lanthanide nitrate hydrate:urea “Type IV” deep eutectic solvents (DES; Ln = Ce, Pr, Nd) were prepared and their physical properties measured, showing very high surface tension and density, with low viscosity and glass transition temperatures. Calculated Gordon parameters were similar to water, with lower molecular volumes than “Type III” DES. The LnDES were used as reaction media for efficient combustion synthesis of lanthanide oxides. The nanostructure of the Ce(NO₃)₃·6H₂O:urea DES was measured using neutron and X-ray scattering and resolved with empirical potential structure refinement (EPSR) atomistic modeling. The models showed the existence of strongly bonded yet fluxional oligomeric [-Ce-NO₃-] polyanions and polycations. Because of the excess of the molecular component in the mixture, an intercalating H-bonded nanostructure containing mainly water and urea was observed, which can be considered as a lubricating molecular pseudophase. This dichotomous structural observation helps to explain some of the unusual physical properties such as low viscosity and high surface tension, while also challenging the fundamental definitions of DES.

A series of graphitic carbon nitride (CN) in the form of nanosheets with porous structure have been prepared through thermal treatment of bulk CN in air. Compared with the bulk counterpart, the as-generated holey CN nanosheets are larger in specific surface area. Endowed with more active sites and enhanced mass transport ability, the latter display catalytic performance substantially superior to the former, exhibiting higher H₂S conversion and S selectivity in the oxidation of H₂S to S. Moreover, the CN nanosheets show much better durability than traditional catalysts. It is envisaged that the strategy is a general technique that can be extended to produce porous CN nanosheets from other nitrogen-rich precursors, as well as to prepare other 2D carbon-based materials for potential applications.

Vehicle lightweighting strategies must deliver sustainable returns to customers and society. This work evaluates the sustainable return on investment (SROI) of lightweighted advanced high strength steel (AHSS) and carbon fiber reinforced polymer (CFRP)-intensive multimaterial bodies in white (BIWs) for automobiles. The SROI depends on the lightweighted BIW’s manufacturing cost and the difference in sustainable cost between a baseline (mild steel) BIW and the lightweighted alternative. The sustainable cost is the sum of the customer’s lifetime fuel (or electricity) costs and the costs of environmental externalities. A cradle-to-grave life cycle assessment (LCA) was conducted to quantify the environmental impacts of CFRP and AHSS BIWs in gasoline-fueled cars, bioethanol (E85)-fueled cars, and battery electric vehicles (BEVs) driven for a lifetime distance of 200 000 km. For cars fueled with gasoline- or corn-based bioethanol, the CFRP BIW yielded the lowest SROI; the AHSS BIW performed best for BEVs and cars fueled with wood bioethanol. However, the commercial availability of recycled carbon fiber should increase the SROI of the CFRP BIW in the future. Additionally, the SROI of CFRP BIWs is maximized when carbon fiber production is done using energy from a low carbon-intensity electric grid or decentralized sources such as waste-to-energy incineration plants.

Acrylpimaric acid-modified aminopropyltriethoxysilane (APA-APTES) was prepared and confirmed by FT-IR, ¹H NMR, and ¹³C NMR. The prepared APA-APTES was used as a cross-linking agent in the preparation of modified room-temperature-vulcanized (RTV) silicone rubber. The effects of APA-APTES on the thermal stability and mechanical properties of the modified silicone rubber were investigated. The APA-APTES-modified RTV silicone rubbers have significantly improved thermal stability and mechanical properties compared with unmodified silicone rubber. Such improved properties are due to the presence of hydrogenated phenanthrene ring in APA-APTES, which induces a cross-linking network structure in the modified RTV silicone rubber. In addition, RTV silicone rubber modified with APA-APTES also exhibited better performance than that modified with rosin acid or bisphenol A. This work also demonstrates that a rigid structure dispersed in silicon rubber can more effectively improve the rubber’s properties.

Cellulose esters are cellulose derivatives with broad application in plastics, films, fibers, coatings, textiles industries, and so forth. Taking cellulose acetate propionate (CAP) as an example, high-viscosity CAP products are widely used in printing inks, hot-melt dip coatings and lacquer coatings, and so forth. However, it was and remains to be a great challenge to manufacture high-viscosity CAP derivatives because of the overuse of sulfuric acid as catalyst that can degrade cellulose and then affect the viscosity and molecular weight of the product. Herein, with use of the copolymer of divinylbenzene with 4-vinylbenzyl chloride (PDVB–VBC) as support, imidazole-containing ionic liquid (IM) as linker, and polyoxometalates (POMs) as catalytic active sites, novel solid acid catalysts of PDVB–VBC–IM–POMs are prepared and fully characterized by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, nuclear magnetic resonance, Brunauer–Emmett–Teller, thermogravimetry-differential scanning calorimetry, and X-ray photoelectron spectroscopy. Application of the as-prepared catalysts for CAP shows the following advantages: (1) high viscosity and high molecular weight (Mw) of CAP can be achieved; (2) partially substituted CAP product (degree of substitution, 2.18–2.77) can be obtained without necessity of the hydrolysis step, in which the relatively higher substitution degree of cellulose takes place at the C₆ position. This work shows the great potential of new designed solid acid catalyst for high value-added cellulose derivatives.

We develop four kinetic models of varying complexity for biodiesel production. The models incorporate both transesterification and saponification, thereby making them practically applicable. We then propose an iterative parameter estimation algorithm to identify a prefixed number of significant rate constants via sensitivity analysis and estimate their kinetic parameters (A and ΔE) using nonlinear regression. Using experimental data on eight different oils, two alcohols, and two catalysts, we show that our models accurately predict the dynamic concentration profiles of various species during the transesterification of oil. Furthermore, we demonstrate the applicability of the best model (based on the values of Mean Absolute Error, Root Mean Square Error, and Akaike Information Criterion) for 11 additional experiments by predicting the final biodiesel properties with significant accuracy. Finally, using N-way ANOVA, we identify the choice of oil, alcohol, and catalyst as the most significant input factors followed by the operating conditions of the reactor.

Phosphoryl ligands of the general formula O═PR₃ (R = Me, OMe, Et, ⁿBu, Ph, ⁱPr, NMe₂) were coordinated to [Nd(TriNOx)] (TriNOx^3– = ([(2-^tBuNO)C₆H₄CH₂]₃N)^3–), and the resulting complexes were characterized. Solution equilibrium constants for each complex were determined, demonstrating a large range for phosphoryl ligands’ Lewis basicity. Thermogravimetric analyses provided evidence for the qualitative thermodynamic preference of phosphoryl ligands for [Nd(TriNOx)] over the dysprosium analogue. These findings were exploited for the separation of binary mixtures of neodymium/dysprosium and lanthanum/neodymium. Implementation of phosphoryl ligands in the TriNOx separation system expands its scope and demonstrates a fundamentally different mode for separating rare-earth cations based on adducts with neutral donors.

The design of antimicrobial surfaces as integral parts of advanced biomaterials is nowadays a high research priority, as the accumulation of microorganisms on surfaces inflicts substantial costs on the health and industry sectors. At present, there is a growing interest in designing functional materials from polymers abundant in nature, such as cellulose, that combine sustainability with outstanding mechanical properties and economic production. There is also the need to find suitable replacements for antimicrobial silver-based agents due to environmental toxicity and spread of resistance to metal antimicrobials. Herein we report the unprecedented decoration of cellulose nanofibril (CNF) films with dehydroabietylamine 1 (CNF-CMC-1), to give an innovative contact-active surface active against Gram-positive and Gram-negative bacteria including the methicillin-resistant S. aureus MRSA14TK301, with low potential to spread resistance and good biocompatibility, all achieved with low surface coverage. CNF-CMC-1 was particularly effective against S. aureus ATCC12528, causing virtually complete reduction of the total cells from 10⁵ colony forming units (CFU)/mL bacterial suspensions, after 24 h of contact. This gentle chemical modification of the surface of CNF fully retained the beneficial properties of the original film, including moisture buffering and strength, relevant in many potential applications. Our originally designed surface represents a new class of ecofriendly biomaterials that optimizes the performance of CNF by adding antimicrobial properties without the need for environmentally toxic silver.

The biomass-derived source, low-cost and hydrophobicity/oleophilic advantages of activated carbon (AC) were explored for the immobilization of Aspergillus oryzae whole-cells expressing Fusarium heterosporum lipase. The adsorptive influence of AC favored growth of the cells into its porous interfaces with paralleled exterior dense film formation. Increasing AC weights hindered extracellular lipase activity. Cell aggregation of 0.34 ± 0.02 mg/BSP was found to be effective in catalyzing an industrially challenging feedstock (68.77% w/w free fatty acids, 20.48% w/w triglycerides) to 98% fatty acid methyl esters (FAME). In a comparative investigation with polyurethane as matrix, higher trans/esterification facilitation was observed with AC. Benefiting from the oleophilicity of AC; denaturation effect from methanol on the lipases was reduced. Surface characterization with FE-SEM, XPS and FT-IR evidenced effective cell-matrix adhesion and a retention of the AC’s intrinsic properties. The advantageous tribology of AC ensured recyclability of the matrix for fresh cells immobilization. Comparable FAME (98.08% w/w) was achieved with the recycled matrix in successive batches. The spent-matrix valorization approach, thus, proposes sustainable biorefineries with immobilized lipase catalyzed biodiesel production.

Due to increasing demand of natural antioxidants for pharmaceutical, food and cosmetic applications, extraction of polyphenols from natural resources has received enormous attention. In this regard, microalgae biomass exhibits great potential for target bioactive compounds accumulation. Conventionally, petroleum-derived volatile organic solvents (VOCs) and water have been used to recover polyphenols from biomass; however, VOCs are hazardous, nonenvironmentally friendly solvents while water suffers from coextraction of other impurities. Therefore, the goal of this work is to evaluate renewable deep eutectic solvents (DES) as alternative to conventional solvents for recovering polyphenols from microalgal biomass. In particular, Chlorella vulgaris was subjected to solvent extraction using 12 DES systems composed of choline chloride (ChCl) and polyols including glycerol (Gly), ethylene glycol (EG), 1,3-propanediol (PDO) and 1,4-butanediol (BDO) and two benchmark conventional solvents, namely ethyl acetate and water. Initially, the extraction efficiency was assessed based on total phenolic content (TPC) via Folin–Ciocalteu method, as the most favorable operating conditions were determined (i.e., temperature of 60 °C, extraction time of 100 min and 20:1 solvent to biomass ratio). Afterward, solvent extracts were analyzed for their antioxidant activity via DPPH free radical scavenging method and their polyphenolic profiles were characterized via chromatographic analysis, with major phenolic compounds being gallic acid, caffeic acid, p-coumaric acid and ferulic acid. Furthermore, biomass surface characterization was performed via scanning electron microscopy (SEM) to further understand the effect of the solvents during the extraction process. Overall results support that polyol-based DES outperformed conventional solvents in terms of polyphenolic extraction efficiency, antioxidant activity of the extracts and selectivity of target antioxidants from Chlorella vulgaris, setting the grounds for developing more sustainable extraction processes for recovering natural antioxidants from microalgae biomass.

The purpose of this research is to develop an effective and inexpensive oxygen evolution reaction (OER) electrocatalyst to achieve high-efficiency water decomposition. Herein, Keggin-type polyoxometalate (POM) nanoparticles coated with zeolitic imidazolate framework (ZIF-67) were successfully synthesized by facile methods. An efficient ZIF-67@POM catalyst with yolk/shell structure is reported. The POM nanomaterials are uniformly dispersed in the surface of ZIF-67. This unique yolk/shell structure with potential synergistic interaction between POM and ZIF-67 results in superior electrocatalytic activity in OER. When the current density is 10 mA cm^–2, the overpotential is only 287 mV, and the Tafel slope is 58 mV per decade. Moreover, the as-prepared yolk/shell ZIF-67@POM catalysts exhibit excellent cycling stability, high surface area, abundant surface active sites, and high diffusion efficiency comparable to the traditional noble-metal-free OER electrocatalyst.

H-BiVO_4–x:Mo was successfully deposited on microwire-structured silicon substrates, using indium tin oxide (ITO) as an interlayer and BiOI prepared by electrodeposition as precursor. Electrodeposition of BiOI, induced by the electrochemical reduction of p-benzoquinone, appeared to proceed through three stages, being nucleation of particles at the base and bottom of the microwire arrays, followed by rapid (homogeneous) growth, and termination by increasing interfacial resistances. Variations in charge density and morphology as a function of spacing of the microwires are explained by (a) variations in mass transfer limitations, most likely associated with the electrochemical reduction of p-benzoquinone, and (b) inhomogeneity in ITO deposition. Unexpectedly, H-BiVO_4–x:Mo on microwire substrates (4 μm radius, 4 to 20 μm spacing, and 5 to 16 μm length) underperformed compared to H-BiVO_4–x:Mo on flat surfaces in photocatalytic tests employing sulfite (SO₃^2–) oxidation in a KPi buffer solution at pH 7.0. While we cannot exclude optical effects, or differences in material properties on the nanoscale, we predominantly attribute this to detrimental diffusion limitations of the redox species within the internal volume of the microwire arrays, in agreement with existing literature and the observations regarding the electrodeposition of BiOI. Our results may assist in developing high-efficiency PEC devices.

Graphene films promise great application potential in modern electronic devices due to their superior electrical and thermal conductivities. However, the green manufacturing of graphene films is still faced with challenges. Also, graphene films prepared by the oxidation and exfoliation method are expensive and exhibit poor mechanical properties. In this work, the highly conductive graphene-based film with reinforced mechanical strength is fabricated by employing cellulose nanofiber (CNF) to help expandable graphite (EG) exfoliate directly in aqueous solution and poly(ethylene oxide) (PEO) to construct a nacre-like structure. Herein, we succeeded in addressing the issue of the graphene films’ unsatisfactory cost and mechanical properties by using very cheap EG as the raw material and taking advantage of the synergistic performance of the two-dimensional EG nanoplatelet, one-dimensional CNF, and flexible PEO. When the mass ratio of EG, CNF, and PEO reaches 95:5:3, the graphene-based film displays a relatively high tensile strength (about 63.3 MPa), which shows a 587% increase over that of EG film (9.2 MPa) and is much higher than those of the reported graphene films prepared through physical exfoliation to our knowledge. Moreover, it shows extraordinary electrical conductivity (1226 S cm^–1), thermal conductivity (302.3 W m^–1 K^–1), and electromagnetic interference shielding effectiveness (44 dB with a thickness of 12 μm). In summary, the manufacturing route of the EG/CNF/PEO composite film is efficient, economical, and promising for commercial applications in the contemporary electronic industry.

Seeking economical, high-performance catalysts from natural waste to substitute traditional noble metal catalysts has been an emerging strategy in recent decades for energy catalysis and conversion devices. In this work, sustainable biomass kelp-derived self-nitrogen doped porous biomass carbon (PBC) with tunable pore structure and large specific surface areas was skillfully developed. The effect of calcination temperature on the pore structure and morphology of PBC was investigated to further optimize its performance. Honeycomb-like PBC exhibited high specific surface areas (805.2 m² g^–1) and remarkable catalytically active nitrogen sites (higher to ∼1.51 wt %) with quantitative analysis. It largely enhanced its electrochemical performance such that the PBC-800 material showed excellent oxygen reduction reaction activity, and the electron transfer path of this process was fully explained by simulated density functional theory calculations. Interestingly, it possessed a high adsorption capacity for gaseous toluene (model fitted value of 332.23 mg g^–1). On the basis of the above excellent properties, this kelp-based PBC might serve as a potentially bifunctional material for energy conversion and environmental purification.

Covalent organic frameworks (COFs) are a new class of lightweight crystalline organic porous materials that are covalently constructed from organic building blocks. However, it is very difficult to construct the functional COFs. It is particularly very complicated to construct chiral covalent organic frameworks (CCOFs), because asymmetry, porosity, and crystallinity must be contemporaneously taken into account. Here, we prepared two CCOFs, termed TPB2-COF and Tfp2-COF, by directly employing chiral organo-catalysts as building units. Because of the precisely one-dimensional pore channels with periodically appended of chiral organo-catalytic sites as well as the ability to accurately control the environment around chiral organo-catalytic sites, these obtained CCOFs could serve as effective heterogeneous catalysts for an asymmetric Steglich rearrangement and Asymmetric Michael addition, with the stereoselectivity and diastereoselectivity up to 84% enantiomeric excess (ee) value and 86% ee value, 17:1 diastereomeric ratio (dr) value for asymmetric Steglich rearrangement and asymmetric Michael addition, respectively, rivaling or surpassing the homogeneous and amorphous analogues. Our strategy may be used to synthesize a series of functional COFs for a variety of applications.

In this study, a recovery strategy of turning cathode materials of waste lithium-ion batteries, lithium cobalt oxide (LiCoO₂), into high-performance catalysts for the oxidation of airborne benzene is investigated. Part of the Co³⁺ in LiCoO₂ was leached out from the [CoO₆] octahedra by HNO₃ solution via the disproportion reaction with the deintercalation of interlayer Li⁺ ions, resulting in the formations of Li, Co, and O vacancies. The presence of Li and O vacancies facilitated gaseous benzene adsorption and subsequent activation of adsorbed benzene, and the Co vacancies together with the oxygen vacancies induced the generation of plenty of active surface oxygen species, accordingly the catalytic activity of the acid-modified LiCoO₂ was greatly improved with good resistance to the alternative “heating-cooling” operation and stability from 0.8 to 2.3 vol % of humidity. More importantly, the acid modification process is green since the HNO₃ solution could be reused many times to produce effective catalysts, and the final solution containing high concentrations of Li⁺ and Co²⁺ ions could be potentially recycled for cathode material manufacturing. The acid treatment method also worked effectively with the commercial LiCoO₂. This study would inspire the development of novel and sustainable catalytic systems for environmental applications.

This paper analyzes and compares the life cycle environmental impacts of two major types of Li-ion batteries using process-based and integrated hybrid life-cycle assessment (LCA) approaches. The life cycle inventories (LCIs) of Li-ion battery contain component production, battery assembly, use phase, disposal and recycling and other related background processes. For process-based LCA, 17 ReCiPe midpoint environmental impact indicators and three end point environmental impact indicators are considered. As for the integrated hybrid LCA study, life cycle greenhouse gas (GHG) emissions and energy consumption are emphasized. Furthermore, we perform sensitivity analysis of life cycle GHG emissions with respect to the uncertainties in product prices, mass of BMS and cooling system, and production efficiency. The integrated hybrid LCA results show that battery cell production is the most significant contributor to the life cycle GHG emissions and the economic input-output (EIO) systems contribute the largest part in life cycle energy consumption for both types of Li-ion batteries. The most significant difference between two Li-ion batteries lies in the disposal and recycling stage. For LiMn₂O₄ (LMO) battery, the disposal and recycling stage only makes up a small portion of less than 10% for life cycle GHG emissions and energy consumption. However, for Li(Ni_xCo_yMn_z)O₂ (NCM) battery, it contributes a significant part at more than 20%.

Carbon fiber (CF) is a promising material as carbon-based electrode and support for flexible supercapacitors. However, it still suffers from narrow voltage in the aqueous electrolyte due to the water decomposition (1.23 V). Herein, an aerobic pyrolysis is developed to recover aligned carbon fibers from carbon fiber reinforced polymers. More importantly, during this oxygen existence condition, the surface of reclaimed carbon fibers (RCFs) is etched into groove-shaped structure and modified by introducing abundant oxygen-containing functional groups, which significantly expands the negative potential window of RCFs-based electrode to −1.4 V (vs standard calomel electrode) and the working voltage of RCFs-based symmetric supercapacitor to 2.4 V in an aqueous electrolyte of 1.0 M Na₂SO₄, with capacitance retention of 90% and 93.6% after 10 000 cycles, respectively. This work well matches the aerobic pyrolysis of recovery of CFs from CFRPs and electrochemical performances of RCFs, supplying a new strategy to develop high-performance energy storage device.

Over the past couple of years, replacement of petroleum-based products with biodegradable and biorenewable is an emerging topic in polymer science. Biodegradable polyglycolic acid (PGA), the simplest aliphatic linear polyester, can traditionally be synthesized through the ring-opening polymerization of glycolide. Our previous studies revealed that PGA can alternatively be produced via one-step cationic polymerization of formaldehyde from trioxane and carbon monoxide (CO), which are potentially sustainable C1 feedstocks, under Brønsted acidic conditions. In this study, trioxane, CO, and a minor amount of fatty ester epoxides are copolymerized to improve on the physical properties of PGA, such as solubility and appearance, under the same reaction conditions for PGA homopolymer synthesis (in DCM, at 800 psi CO, with triflic acid catalyst, reaction duration of 72 h). The results have shown that the addition of minor quantities of epoxide comonomers vastly improved the solubility and decreased the melting temperature of the PGA. The melting temperatures of the obtained copolymers decreased by increasing incorporation percentages of the epoxide comonomers and decreasing polymerization temperatures. The solubility of the copolymers increased with incorporation of the epoxides in the PGA backbone.

The aim of the present work was to study the antioxidant capacity of spry dried whey permeate (WP) that was subjected to a cathodic electroactivation. In this context, electroactivation technology was applied to WP to in situ convert a part of lactose into lactulose (prebiotic) with a simultaneous inducing of Maillard reactions products (MRPs) which are known to have high antioxidant capacity. The antioxidant activity (AA) of the electroactivated and dried whey permeate (EAWP) was evaluated by the DPPH scavenging activity, reducing power, ABTS^•+ radical scavenging assay, and iron chelating capacity. The effect of the drying temperature on the AA of the EAWP was also evaluated. The obtained data demonstrated that electroactivation significantly (p < 0.001) enhanced the AA of WP and that this AA was mainly due to the intermediate MRPs, as shown by the highest absorbance at 294 nm. Moreover, the results showed that the drying temperature significantly influenced the AA of EAWP.

Band structure and crystallinity engineering of polymeric semiconductors provides effective strategies for photocatalytic activity enhancement. Here, a facile one-step ionothermal method was developed to achieve the in situ growth of carbon nitride (CN) isotype heterojunctions (ms-CN-x) using KCl/LiCl eutectic salts as the high-temperature solvent and urea as the starting material, which are demonstrated to be efficient photocatalysts for removal of toxic heavy metal and organic pollutant in a single or coexisting system. The as-obtained ms-CN-x composite material appears as well-ordered nanorod structure with high crystallinity and consists of phases of both heptazine-based CN and triazine-based CN. With structural and morphological merits, the ms-CN-0.5 photocatalyst exhibits remarkable adsorption–photodegradation performance for high-level methylene blue (MB). Moreover, simultaneously enhanced photocatalytic reaction rate of Cr(VI) reduction and MB oxidation over ms-CN-0.5 are achieved and systematically investigated, which benefits from improved crystallinity, increased visible-light absorption, and promoted charge-carrier separation via one-dimensional heterojunction nanorods. On the basis of the reactive species study, a synergistic reduction–oxidation elimination mechanism is revealed, indicating that the photogenerated holes are primary active species for MB degradation, which are rapidly scavenged by MB in the Cr(VI)/MB coexisting solution, and the photoexcited electrons are responsible for the reduction of Cr(VI). Our work may provide new insight into the future design of efficient polymeric materials toward practical applications in the environment and energy chemistry.

Wood is a versatile raw material valued highly for its abundance, low cost, biocompatibility, and natural composition. It has drawn increasing interest for its uses in green electronics, biological devices, and energy storage. Meanwhile, its potential application in water purification has not been adequately explored. This study reports the development of a wood-based filter decorated with silver nanoparticles (Ag NPs) and its application for water purification. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the successful loading of Ag NPs on the surfaces of the wood mesoporous network. The effects of Ag NP content and filter thickness on the decomposition of methylene blue (MB) and bacterial removal were evaluated. The prepared Ag/wood filter can remove more than 98.5% of MB via physical adsorption and catalytic degradation. After the Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) suspensions passed through the Ag/wood filter, the inactivation and removal of E. coli and S. aureus reached up to 6 and 5.2 orders of magnitude, respectively. The findings demonstrate that the prepared Ag/wood filter, which is biomass based and easy to handle, has a potential for point-of-use water purification.

In the present study, onion extract was used for green synthesis of iron oxide nanoparticles (Fe-NPs). The X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy characterizations demonstrated that the biosynthesized Fe-NPs were mainly composed of low-crystalline or amorphous Fe₂O₃ with diameter of 19–30 nm. The effect of seed priming with different concentrations of Fe-NPs (20, 40, 80, and 160 mg L^–1) on seedling growth parameters, photosynthetic pigments, antioxidant potential, metabolites, and hormonal profiles of diploid and triploid watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) varieties were  studied on the third and eighth days of seedling development. Seed priming with Fe-NPs was safer compared to its bulk counterparts (FeCl₃ and Fe₂O₃) and had no toxic impact on seed germination, seedling development, and chlorophyll biosynthesis at studied concentrations. Untargeted metabolomics studies showed that different Fe-NPs priming treatments distinctly altered the metabolome of diploid and triploid watermelon seedlings. Uniquely, we found that different Fe-NPs priming treatments significantly modulate the 12-oxo phytodienoic acid (OPDA) level in diploid and triploid watermelon seedlings. In conclusion, seed priming with nontoxic Fe-NPs can be applied sustainably to increase nonenzymatic antioxidant potential as well as to prime or induce jasmonates-linked defense responses in watermelon seedlings.

All-inorganic CsPbX₃ (X = I, Br, Cl) perovskite nanocrystals (NCs) have attracted much attention in clean energy fields such as solar cells and light-emitting diodes due to their excellent opto-electric properties. Herein, we extended the application of perovskite NCs to the photocatalytic degradation field. We demonstrated a facile strategy for highly efficient and feasible synthesis of pure CsPb(Br_1–xCl_x)₃ NCs and CsPb(Br_1–xCl_x)₃-Au nanoheterostructures. The photocatalytic performance of CsPb(Br_1–xCl_x)₃-Au for degrading water-insoluble carcinogenic Sudan Red III under visible light irradiation was characterized by UV–vis absorption spectra. CsPb(Br_1–xCl_x)₃-Au nanoheterostructures showed excellent photocatalytic activities, which can degrade about 71% of Sudan Red III within 6 h. This study provides a new way to use semiconductor perovskite–metal nanoheterostructures in photocatalytic applications.

A novel ingenious and ultrasensitive chiral electrochemical transducer is proposed for tryptophan (Trp) isomer detection by using electroactive Au@Ag NPs as electrochemical tags. Moreover, the large binding constant of d-Trp on NPs and strong interaction between d-Trp and Cu²⁺ cause electroactive Au@Ag NP to assemble on the electrode, generating strong differential pulse voltammetry (DPV) signals from the oxidation of Ag⁰ to Ag⁺. In sharp contrast to d-Trp, l-Trp leads to the assembly of Au@Ag NP oligomers on the electrode, resulting in a weak DPV signal. The distinct DPV responses enable the developed electrochemical chiral transducer for the sensitive and accurate quantification of d-/l-Trp. The limit of detection (LOD) is 1.21 pM for d-Trp. This established electrochemical chiral sensor also achieves the specific determination of enantiomeric excess. In comparison to other reported approaches, this proposed electrochemical chiral sensor excels by its sensitivity, simplicity, and good availability of electroactive Au@Ag NP assemblies. Target-induced colorimetric assays can be converted into electrochemical assays for the dual signal amplification in the field of ultrasensitive enantioselective chiral discrimination.

The first Life-Cycle Assessment (LCA) of an acid-free, microwave-assisted process for pectin production at pilot scale is reported. The properties of the resulting pectin were measured and compared against the criteria for commercial pectin, while the energy consumption of the microwave process was measured to compare its life cycle impacts with that of the current commercial process. Overall, the pectin met all the criteria for food-grade commercial pectin. The microwave unit was estimated to have <25% of the environmental impact of traditional acid-assisted thermal process in all categories measured and provided an improved yield of 5% (wet weight basis) compared to 3% by thermal heating under normalized conditions. The readouts were comparable with each other over three runs indicating a robust and reproducible process, crucial for scale-up purposes. With the product meeting the relevant criteria and the process being robust and more environmentally friendly, this work demonstrates the practical and commercial potential of microwave technology to succeed conventional acid-based extraction of pectin production.

Metal chloride has shown high potential in biomass conversion to valuable chemicals, but the nature of active species and the corresponding performances on each successive reaction step need further elucidation. In this work, SnCl₄ was found to exhibit satisfactory catalytic activity, achieving 64.6 mol % yield of levulinic acid from corncob residue. The levulinic acid obtained could be further converted to more valuable ethyl levulinate with 85% yield without any extra catalyst addition. In water medium, the hydrolysis of SnCl₄ resulted in the formation of stannic oxide, H⁺ and Cl^–, which showed a synergistic effect and all contributed to levulinic acid production. It was demystified that Cl^– promoted cellulose hydrolysis, and the formed H⁺ as Brønsted acid mainly contributed to cellulose hydrolysis and fructose dehydration, as well as HMF decomposition to levulinic acid. Sn(IV) species facilitated both glucose-to-fructose isomerization and fructose consumption yielding undesirable polymers, but exhibited a negative influence on cellulose hydrolysis. The proposed kinetic model showed a good fit with the experimental result, and further confirmed the proposed catalytic mechanism. The insights reported here might give some useful information for the development of effective catalysts to produce valuable chemicals directly from raw lignocelluloses.

Levulinic acid esters (LAEs) were synthesized from α-angelica lactone and alcohols, in a reaction catalyzed by a new family of chloride-free Lewis acidic ionic liquids, containing trifloaluminate anions, [Al(OTf)_3+n]ⁿ⁻. Changing the catalyst from poorly soluble Al(OTf)₃ (used as suspension) to fully homogeneous trifloaluminate ionic liquids resulted in shorter reaction times required for full α-AL conversion (60 min at 60 °C for 0.1 mol % catalyst loading) and unprecedented selectivities to LAEs, reaching >99%. Supporting the trifloaluminate ionic liquid on multiwalled carbon nanotubes gave an easily recyclable system, with no leaching observed over six cycles. Mechanistic considerations suggest that the propensity of Al(OTf)₃ to undergo very slow hydrolysis results in the correct balance of Brønsted and Lewis acidic sites in the system, which inhibit byproduct formation.

Previous work has shown that sulfonation post-treatment employed at a temperature of 130–140 °C modifies the lignin in steam-pretreated softwood to improve the ease of hydrolysis of the resulting “post-treated” substrate. Sulfite has also been shown to detoxify water-soluble fractions originating from the steam pretreatment of softwood to enhance fermentation. Consequently, lignin modification and detoxification could be combined in a single process step to simultaneously improve the ease of hydrolysis and fermentability of a high solids (25% w/v) substrate which contains the combined 5% (w/v) water-soluble and 20% (w/v) water-insoluble fractions (“high solids whole slurry”), originating from the steam pretreatment of softwood biomass. Unlike previous work on sulfite post-treatment applied to the water-insoluble fractions of steam-pretreated softwood, the sulfite treatment of the steam-pretreated softwood high solids whole slurry was effective when performed at a reduced temperature (70 °C) when sodium carbonate was added as an alkali source. The alkaline sulfite treatment increased the enzymatic hydrolysis yield of the high solids whole slurry from 55% to 67% while simultaneously improving fermentability, resulting in an ethanol concentration of 56.4 g/L.

Rapid and sensitive identification of tumor biomarker or cancer cells in their nascent stage based on surface-enhanced Raman scattering (SERS) is still an attractive challenge due to the low molecular affinity for the metal surface, the complexity of the sample, and low-efficiency use of hot spots in one- or two-dimensional geometries. Here, we demonstrated a novel kind of renewable CuFeSe₂/Au heterostructured nanospheres that are hierarchically porous for specific and sensitive detection of lung cancer biomarkers of aldehydes and lung cancer cells. The heterostructured nanospheres were constructed by loading an Au shell formed by photoreduction on the CuFeSe₂ frameworks. P-aminothiophenol (4-ATP) as a Raman-active probe molecule was first grafted on CuFeSe₂/Au nanospheres, and then the gaseous aldehyde molecules were sensitively bonded onto the nanospheres by formation of a C═N bond with a detection limit of 1.0 ppb. Moreover, the resulting folic acid (FA)-conjugated nanospheres have a high SERS activity to Rhodamine B isothiocyanate (RBITC), which can be used to specifically recognize and sensitively detect the A549 cells. Our study suggested that the synthesized renewable CuFeSe₂/Au heterostructured nanospheres as a multimodal platform could find a wide range of applications in the fields of medicine, biotechnology, and environmental sciences.

While lithium sulfur batteries (Li–S) hold promise as future high energy density low cost energy storage systems, barriers to implementation include low sulfur loading, limited cycle life, and the use of toxic electrolyte solvents. A comprehensive study of Li–S cells in the environmentally benign di(propylene glycol) dimethyl ether (DPGDME)-based electrolyte, using as-prepared MoS₂ nanosheets derived from a facile aqueous microwave synthesis as polysulfide trapping agents, is reported herein for the first time. Conventional coated foil electrodes and binder-free electrodes (BFEs) with various structures are systematically generated and tested to correlate electrode design with the resulting electrochemical behavior. Significantly improved Li–S electrochemistry is demonstrated through the synergy of MoS₂ chemistry and binder-free electrode engineering. In the coating configuration, the MoS₂-containing cell evinced better rate performance and more stable cyclability than the cell without MoS₂. In comparison with the coating counterparts, the BFE cells exhibited excellent cycle stability and superior rate capability (10-fold capacities and energy density per electrode weight with 20% higher retention rate) despite 2X higher areal sulfur loading. The BFE cell improvement can be attributed to the synergistic effect of the i) interconnected macroporous structure of CNT interlayers, providing a conductive framework, and ii) the efficient polysulfide trapping by the MoS₂ nanosheets.

Carbon nitrides are promising hosts for single-atom catalysts (SACs) based on small amounts of precious metals dispersed as isolated atoms, presenting tantalizing opportunities to reduce the cost and for higher efficiency as compared to traditional nanoparticle-based formulations. Heteroatom doping represents a straightforward method to tailor the (opto-)electronic properties of carbon nitrides and could, therefore, extend the tunability of SACs. This paper compares the impact of modifying graphitic carbon nitride with phosphorus, boron, sulfur, and fluorine on the interaction with palladium. As an aliovalent dopant, phosphorus is found to appreciably increase the electron density of carbon nitride, thereby lowering the oxidation state of the metal. The stability of single atoms depends on the dopant (D) content, with nanoparticle formation observed at higher concentrations (e.g., molar D:Pd ratio >1), which is linked to a weaker metal–host interaction. Evaluation in the three-phase semihydrogenation of 2-methyl-3-butyn-2-ol, an important building block in fine-chemical manufacturing, evidences an enhanced reaction rate (up to 5.4 times) upon doping with phosphorus that is governed by the P/Pd molar ratio. The selectivity to the desired product approaches 100%, outperforming the commercial Lindlar-type Pd-Pb/CaCO₃ catalyst (78%). Looking toward the future implementation, scalability aspects of SACs based on carbon nitrides, such as the choice of precursor, synthesis conditions, and the trade-off between the host surface area and yield, are addressed. Extrapolation of the superior catalytic properties and robust stability are confirmed in a continuous-flow reactor. These findings identify key steps in the design of single-atom catalysts based on carbon nitride for large-scale application.

Flexible and wearable supercapacitor (SC) fabrics have received considerable research interests recently. However, their high hydrophobicity, poor conductivity, inferior capacitance, and low energy density remain a bottleneck to be solved. Herein, a highly flexible and conductive carbonized cotton fabric (CCF) covered by a unique nanostructured Ni(OH)₂ layer is fabricated via a facile high-temperature carbonization process, followed by an electrochemical deposition (ED) treatment. The nanostructured Ni(OH)₂ greatly improves the hydrophilicity of CCF to promote electrolyte penetration and offers abundant electroactive sites, leading to dramatically increased specific capacitance and operating potential window (OPW). The resultant Ni(OH)₂@CCF is then applied as the electrode for an aqueous symmetric SC device. This device has an OPW of 1.4 V and exhibits a high specific capacitance of 131.43 F g^–1 at the current density of 0.25 A g^–1 with a high energy density (35.78 Wh kg^–1 at a power density of 0.35 kW kg^–1, and it can reach 18.28 Wh kg^–1 at a high power density of 14.00 kW kg^–1), which outperforms the performance of most aqueous symmetric SCs. In addition, the SC demonstrates excellent capacitance stability under various bending conditions, suggesting its potentials in flexible and wearable energy-storage devices.

Metal–organic framework (MOF)-derived nitrogen-doped porous carbon as electrode material for supercapacitors has recently drawn much attention. However, the development of flexible electrodes composed of MOF-derived carbon is still a great challenge. Herein, nitrogen-doped porous carbon polyhedra (NC) derived from zeolitic imidazolate framework-8 (ZIF8) are assembled into flexible nanopapers assisted with reduced graphene oxide (rGO). The resultant NC/rGO nanopaper shows a hierarchical structure of NC nanoparticle-imbedded rGO framework. A uniform dispersion of NC nanoparticles is achieved due to the rGO framework, and meanwhile, the uniform decoration of NC nanoparticles on rGO nanosheets prevents easy restacking of rGO. A conductive rGO framework further accelerates the electron/ion transportation inside the NC/rGO nanopaper. Furthermore, excellent mechanical performance of rGO framework endows high flexibility to the NC/rGO nanopaper. As a result, the NC/rGO nanopaper as a binder-free electrode delivers high specific capacitance of 280 F g^–1 at 1 A g^–1, high capacitance retention after 5000 cycles, and high energy density of 19.45 W h kg^–1.

Electrocatalytic reduction of carbon dioxide to high value-added chemicals is essential for sustainable development of human civilization. Seeking catalysts with high activity, selectivity, stability, and low cost is vital for CO₂ conversion. Heteroatom doped carbon materials have proven to be very promising catalysts for CO₂ reduction due to their low cost, high surface area, high conductivity, and excellent stability as well as high electrochemical activity. Herein, we report a N-doped nanoporous carbon sheet derived from cheap and renewable biomass Typha with high surface area, pore volume, and pyridinic N content, which achieved a much higher selectivity (90%) for CO at a much lower overpotential (−0.31 V) than most N-doped carbon materials. The calcination temperature has a great effect on porous structure and the kinds of N species in the catalyst, in which the pyridinic N species play important roles in catalytic performance.

The presence of low-molecular-weight organic acids (LMWOAs) dramatically influences the species and adsorption behavior of heavy metal ions (HMIs). The effect of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) on the adsorption of Cu(II) on polyamine resin (PAMD) was investigated by tracking the evolution of amino groups on the PAMD surface and species of Cu(II)–HEDP complexes. First, a simplified proton consumption model was developed to quantify the chemical states of the surface amino groups, which were classified into four categories of different contents and acidity coefficients (pK_a) as 2.78 mmol/g (pK_a1 = 3.00; defined as type A), 4.44 mmol/g (pK_a2 = 6.46; type B), 3.28 mmol/g (pK_a3 = 8.64; type C), and 7.40 mmol/g (pK_a4 = 10.83; type D). Then, based on theoretical calculations and potentiometric titration, the optimum structure of the Cu(II)–HEDP complexes in the bulk solution were determined to be hexacyclic [Cu(II)L]^2–, [Cu(II)HL]⁻, and [Cu(II)H₂L]⁰ with stability constants of 12.64, 7.07, and 3.80, respectively. When B-type amino group has not been deprotonated, the adsorption mechanism of Cu(II) involved coordination between Cu(II)–HEDP complexes and the deprotonated A-type amino group to form ternary complexes of Cu(II)(R-NH₂)₂L rather than electrostatic interaction between Cu(II)–HEDP complexes and protonated amino groups. With increasing deprotonation degree of the B-type amino groups, the complexing affinity of PAMD toward Cu(II) increased, resulting in that the ligand competition between HEDP in the liquid phase and deprotonated B-type amino groups on the surface of PAMD, ultimately achieved ligand substitution to form binary complex Cu(II)(R–NH–CH₂–CH₂–NH₂)₂. This evolution process provides important guidelines for the development of novel chelate adsorbents resistant to interference by LMWOAs. The enhanced adsorption affinity for HMIs by PAMD can be achieved by reducing the heavy metal complex stability with LMWOAs.

Direct CO₂ capture from atmospheric air is gaining increased attention as one of the most scalable negative carbon approaches available to tackle climate change if coupled with the sequestration of CO₂ geologically. Furthermore, it can also provide CO₂ for further utilization from a globally uniform source, which is especially advantageous for economies without natural sources of carbon-based feedstocks. Solid-supported amine-based materials are effective for direct air capture (DAC) due to their high CO₂ uptakes and acceptable sorption kinetics at ambient temperature. In this work, we describe the application of polymer/silica fiber sorbents functionalized with a primary amine-rich polymer, poly(ethylenimine) (PEI), for DAC. Monolithic fiber sorbents composed of cellulose acetate and SiO₂ are synthesized via the dry-jet, wet quench spinning technique. These fibers are then functionalized with PEI (M_w 800 Da) in a simple and scalable postspinning infusion step and tested for CO₂ capture under pseudoequilibrium conditions as well as under breakthrough conditions. An investigation to study the effect of feed flow rate, adsorption temperature, and presence of moisture in the feed on the CO₂ breakthrough performance of a densely packed fiber sorbent module is conducted to highlight the potential application of this class of structured contactors in direct air capture. The pressure drop of these contactors at high gas velocities is also evaluated. Finally, a vacuum-assisted desorption step is demonstrated for production of high-purity CO₂ from both dry and humid ambient air mixtures.

The effect of calcination temperature on the photoelectrochemical properties of TiO₂ nanotube arrays (TNTAs) has been investigated in many studies. Most work focused on improving the photoelectrochemical properties through optimization of the microstructure. In this paper, however, an anatase/rutile phase junction formed in TiO₂ nanotubes has been demonstrated to account for the enhancement of the photoelectrochemical performance. Observations by the UV–visible diffuse reflectance spectra, glancing incidence angle X-ray diffraction (GIA-XRD), and electrochemical impedance spectroscopy indicate that the rutile fraction is at the bottom of the nanotubes while the anatase fraction is at the body of the nanotubes. The TNTAs with a coexistence of about 60% anatase and 40% rutile exhibit optimal performance and show a 1.4-times improved photocurrent density compared with the pure anatase TNTAs. Detailed synchrotron radiation photoemission spectroscopy further confirms the existence and effect of the phase junction. The results suggest photogenerated electrons transfer from the rutile phase to the anatase phase in the nanotubes due to the band edge alignment, which facilitates the photogenerated carriers separation and transport along the nanotubes and leads to apparent enhancement of the photoelectrochemical behavior.

An effective heterogeneous nanocatalyst was successfully designed by immobilization of tungstate ions (WO₄^2–) onto the modified surface of carbon quantum dots (CQDs) with the 1-aminopropyl-3-methyl-imidazolium chloride ([APMim][Cl]). In this work, for the first time, the synthesized CQDs@IL/Cl^–, via a facile one-step hydrothermal method, was used as an adsorbent and stabilizing support for tungstate ions. Characterization of the synthesized nanoparticles (NPs) by various physicochemical techniques illustrated that tungstate ions have been immobilized on the surface of IL-modified CQDs. With this novel nanocatalyst, a variety of primary, secondary alcohols, and other alcohol substrates have been efficiently oxidized to their corresponding aldehydes and ketones in yields of ≥88% with high selectivity (100%). In the presence of CQDs@IL/WO₄^2– as a recyclable nanocatalyst, all alcohol substrates without overoxidation to carboxylic acid were oxidized within 2 h, under a temperature of 70 °C with H₂O₂ as the oxidant. The above catalyst can be readily recycled using a simple extraction and reused consecutive runs under the described reaction conditions without a considerable decrease in the activity and selectivity. In conclusion, this Article offers a novel application for CQD chemistry.

Recently, metal–organic gels (MOGs) appear as a potential alternative to the well-known metal–organic frameworks due to the easier and more straightforward shaping and other unique features. However, the modification of MOGs with noble metal nanoparticles is still in its infancy. On the other hand, developing multifunctional SERS substrate materials with a facile way still remains a great challenge. Herein, silver nanoparticles/metal–organic gels (AgNPs/MOGs) hybrid, a novel dual functional SERS-active platform that is both Raman signal molecule and highly sensitive SERS substrate, was fabricated by a one-pot approach for the first time. The AgNPs/MOGs hybrid, which was obtained by simply mixing 4-(2,2′:6′,2″-terpyridine)-4′-ylbenzoic acid (Hcptpy) and silver ion (Ag⁺), followed by heating without adding extra reducing reagent, exhibited an outstanding Raman signal due to the combination of the Raman label source of Hcptpy and the localized surface plasmon resonance properties of AgNPs, endowing it an excellent SERS platform for permanganate sensing. It is worth noting that Hcptpy plays dual roles of coordination and reduction in the synthesis of the hybrid, namely, as a coordinating agent to coordinate with Ag⁺ to form MOGs and as a reducing agent to in situ reduce Ag⁺ to form AgNPs. These results foresee that this one-pot synthesis of noble metal nanoparticles modified MOGs hybrids is a promising strategy toward the facile and high-yield production of novel binary functional SERS platforms.

Deep eutectic solvents have previously been used as cost-effective and readily available alternatives to conventional ionic liquids. Due to their versatile complexation properties, they are potential lixiviants for selective metal processing. In this study, we investigate the leaching behavior of three choline chloride-based deep eutectic solvents to selectively separate indium and tin from an oxide flue dust material. Ethylene glycol, urea, and oxalic acid dihydrate were used as hydrogen bond donors in the eutectic mixtures. The highest leaching yields were observed in the oxalic acid system Oxaline. A two-step precipitation procedure was developed for the leachate solution to separate the target metals indium and tin from the main flue dust components, i.e., iron, zinc, lead, and copper. This ionometallurgical approach was compared to equivalent leaching experiments using aqueous oxalic acid solutions and other deep eutectic solvents.

A facile approach to a corncob biorefinery, focusing on both carbohydrate valorization and lignin stabilization, was proposed to coproduce platform chemicals (glucose, xylose, arabinose, and furfural) and lignin. Different metal chloride prehydrolyses of corncob in the biphasic system (2-methyltetrahydrofuran/H₂O) were first carried out, followed by enzymatic hydrolysis of treated corncob. It was found that the dissolution and recovery of carbohydrate and lignin were dependent on the prehydrolysis conditions (metal chloride concentration, temperature, and time); 82.9% xylose with 56.2% arabinose was produced at 140 °C for 20 min using 25 mM FeCl₃, and subsequently, furfural was generated in a yield of 60.0% from this hydrolysate-containing biphasic system by increasing the temperature to 180 °C for 120 min. The FeCl₃ prehydrolysis of corncob released 99% xylan, retained 91% cellulose, and showed a significant enhancement in the cellulose enzymatic hydrolysis rate of 4.9-fold as compared to that for raw corncob. The chemical structure of the leftover lignin-linked tricin was similar to that of native lignin according to gas permeation chromatography and two-dimensional ¹³C–¹H correlation heteronuclear single-quantum coherence nuclear magnetic resonance characterization, which provided a useful substrate for the production of fine and bulk chemicals.

Biomass waste has emerged as a novel sustainable and renewable material for fabricating functional materials because of the lightweight and easy manufacturing. Herein, we synthesize a porous Fe₃O₄/carbon fiber (Fe₃O₄/CF) composites derived from bagasse waste by in-situ growth and a graphitization process. The Fe₃O₄ nanocrystals uniformly embedded in porous CF significantly construct the multiple interfaces and hierarchical microstructure of Fe₃O₄/CF composites. Fe₃O₄/CF composites exhibit a maximum reflection loss value of −48.2 dB at 15.6 GHz with a thin thickness of only 1.9 mm. Meanwhile, a broad effective absorption bandwidth of 5.1 GHz covering the frequency range of 12.9–18.0 GHz is achieved. The rough surface, porous structure, and proper component contribute to the improved impedance matching. Meanwhile, the Debye relaxation and interfacial polarization dominantly promote the attenuation ability of the microwave. The enhancement of attenuation ability and impedance matching together account for the superior microwave absorption performance.