ChemSusChem最新文献

Developing sustainable biocatalytic processes requires alternative solvents that support enzyme activity while reducing environmental impact. This study explores the potential to use diformylxylose (DFX), a xylose-derived green solvent, as a cosolvent in enzymatic reactions, and compares its application to reaction outcomes in conventional solvents such as dimethyl sulfoxide (DMSO) and dimethylformamide (DMF). A comprehensive enzyme panel, including ketoreductases (KREDs), lipases as well as transaminases (TAs) and imine reductases (IREDs) was tested for activity and stability in DFX. In the green solvent, the selected KREDs and the immobilized lipase CalB retained high or even superior catalytic activity compared to conventional media, while the selected biocatalysts from other enzyme classes such as TAs, and IREDs exhibited limited compatibility under the tested conditions underscoring the enzyme-specific nature of solvent effects. Notably, the KRED TeSADH W110A achieved full conversion when asymmetrically reducing phenyl-ring-containing ketones at 300 mM substrate concentration in DFX, significantly outperforming reaction conditions with DMSO and DMF (∼40% conversion). Lipase CalB also exhibited remarkable activity, reaching 95% conversion at 300 mM 4-nitrophenyl butyrate loading. The findings highlight DFX as a promising alternative solvent for biocatalysis applications, particularly for KRED- and lipase-mediated reactions.

Electrochemical hydrogenation (ECH) demands precise control over multistep pathways, yet developing selective electrocatalysts remains challenging. Herein, we utilize hierarchical carbonized wood (CW) as a sustainable catalytic support to drive deep ECH reactions. By anchoring ZnO nanosheets within CW's microchannels via facile calcination-impregnation, we engineered ZnO/CW catalysts enriched with Zn and O vacancies that promote CO₂ deep hydrogenation to CH₄. By coupling ZnO/CW and 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF₆)/acetonitrile electrolyte, the system exhibited high CH₄ Faradaic efficiency (FE) of 72.9% at -1.34 V vs. SCE. This performance fundamentally diverged from conventional ZnO/carbon paper (ZnO/CP) which terminates at CO production (62.3% FE), showcasing support-driven pathway redirection. Both experimental and theoretical investigations revealed that CW's porous framework facilitates mass transport while Zn vacancies lower the energy barrier in the CH₄ pathway. The platform's versatility extended to oxalic acid upgrading, where SnO₂/CW achieved selective ECH of oxalic acid to glycolic acid in identical electrolytes. This work establishes biomass-derived defect-rich interfaces as sustainable design paradigm for multistep electrocatalytic hydrogenations.

We report a transition-metal-free and highly selective chemical transformation of levulinic acid into citramalic acid via t-butoxide-mediated enolate chemistry, complementing both the biotransformation of glucose and glycerol using E. coli as well as transition-metal-catalyzed processes based on levulinic acid. The atypical behavior of t-butoxide-classically recognized as a base that favors kinetic enolate formation in carbonyl chemistry-proves crucial for accessing the thermodynamic enolate under elevated temperatures and extended reaction times, thereby directing the reaction toward citramalic acid as the major product. Radical-trapping experiments with TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) and benzoic acid significantly diminished the product yield, indicating the involvement of radical intermediates in the initial oxygenation sequence and providing clear mechanistic insight into the operative pathway. Moreover, citramalic acid serves as a sustainable, bio-based platform chemical that is amenable to downstream valorization into high-value feedstocks, such as unnatural amino acid derivative and itaconic acid.

The hydrogen evolution reaction (HER) stands as a fundamental electrochemical process for sustainable hydrogen production through water splitting. While the hydrogen binding energy descriptor has traditionally guided HER catalyst design, this established framework fails to adequately represent the complexity of operational electrocatalytic interfaces, especially in nonacidic environments where hydroxyl species (OH*) competitively adsorb and substantially influence reaction pathways. This concept systematically examines the competitive adsorption behavior between OH* and H* intermediates during HER. The analysis covers the fundamental origins through which OH* blocks active sites and impedes H* adsorption kinetics. A comprehensive overview is provided of recent advances in catalyst design strategies aimed at mitigating OH* interference, including spatial separation of adsorption sites, promotion of OH* spillover, facilitation of proton exchange processes, and creation of unfavorable binding sites for OH* species. The application of advanced characterization techniques, theoretical computations, and electrochemical methods for probing these interfacial phenomena is thoroughly discussed. Finally, the concept outlines remaining challenges and suggests future research directions to advance the fundamental understanding of electrocatalytic interfaces and guide the development of efficient HER catalysts.

Electrochemical energy storage has long been constrained by the structural instability of solid electrodes and the costly design of liquid-based systems. Here, we report a transformative concrete soft-gel electrode that reconciles mechanical robustness with interfacial fluidity, enabling improved stability in aqueous full batteries. Critically, we uncover the fundamental origin of electrode detachment and propose the Ji-Ran instability criterion, which unifies osmotic pressure, electrokinetic shear, and elastic-adhesive balance into a single quantitative framework. Inspired by structural concrete, the incorporation of BaTiO₃ particles reinforces the soft-gel network, raising elastic modulus, adhesion energy, and interfacial integrity. The resulting full batteries deliver high Coulombic efficiency, mitigated capacity decay, and facile recyclability via water-assisted disassembly. This work establishes a generalizable paradigm for concrete soft-gel electrodes and opens a pathway to sustainable, long-lasting aqueous batteries.

The inherent instability of lithium metal with liquid electrolytes, as well as the performance constraints of typical solid electrolytes, has long shifted efforts to develop lithium metal batteries (LMBs). This review contends that the design approach is evolving from simply combining materials to designing multifunctional, network matrices. We critically investigate the development of cross-linked composite solid polymer electrolytes (C-CSPEs) as constructed platforms in which the polymer matrix is not merely a passive host rather a vital, functionally intrinsic constituent. The crosslinking with appropriate filler enables C-CSPEs to achieve high ionic conductivity, mechanical strength, >4.5 V vs. Li/Li⁺ electrochemical stability window (ESW), and reduce electrode/electrolyte interfacial impedance. This review thoroughly analyzed performance criteria, ionic conductivity mechanism, synthesis methods (physical and chemical blending), and crosslinking approaches (thermal curing, photo or UV curing, and radiation-induced crosslinking) for C-CSPEs. We highlight innovative strategies revolutionizing the field including structural battery composites (SBCs) integrating energy storage with load bearing properties, 3D printing for customizing electrolyte infrastructure, artificial intelligence (AI)-assisted designs for optimize material performance, dynamic C-CSPEs for self-healing properties, and halide-based electrolytes enabling high-voltage stability. By combining these fundamental concepts, this review offers a strategic framework for moving C-CSPEs from a promising research issue to the foundation of feasible high-density LMBs.

Redox-active ionic liquids (ILs) represent a promising class of energy carriers due to their intrinsic ionic conductivity, negligible volatility, and electron-transfer capability. However, the design of ILs capable of reversible multielectron storage is still in its infancy. In this work, we report a family of mixed-valence polyoxovanadate-based ionic liquids (POV-ILs) obtained by combining the highly redox-active, mixed-valence cluster (nBu₄N)₄)₈[V₁₄O₃₄Cl][(MgOH)V₁₃O₃₃Cl] with a series of bulky quaternary ammonium cations. Cation exchange transforms the solid precursor into liquid-like POV-ILs, dramatically enhancing solubility in organic solvents, such as acetonitrile, THF, and glymes, making them ideal compounds for nonaqueous redox flow batteries (NRFBs). Electrochemical studies demonstrate that these POV-ILs retain the reversible multielectron redox activity of the parent cluster across a wide potential window, enabling their use as symmetric electrolytes in NRFBs. Flow-cell demonstration confirms stable multielectron cycling, with electrolyte remixing mitigating capacity fading. By integrating the redox versatility of POVs with the solubility and processability of ILs, this work establishes a new design strategy for redox-active electrolytes and highlights the promise of POV-ILs for next-generation, high-energy-density NRFBs.

The rapid development of electric vehicles and large-scale energy storage is driving the requirements for lithium-ion batteries (LIBs) with high energy density, long cycle life, and enhanced safety. However, the commercial graphite anode (372 mAh g⁻¹) struggles to meet these demands. Transition metal oxides are considered as promising anode alternatives due to higher specific capacity and low cost, while their wide application is limited by volume expansion and low conductivity, resulting in rapid capacity fading and poor rate performance. In 2018, the first application of high-entropy oxides (HEOs) as LIB anodes was reported, which attracted the attention of researchers. HEO anodes exhibit outstanding structural stability and electrochemical reversibility owing to their high-entropy effect, lattice distortion, cocktail effect, and sluggish diffusion. This review summarizes recent works on HEO anodes for LIBs, focusing on their structural types, synthesis methods, and advanced characterization techniques. Moreover, lithium storage mechanisms are discussed. Finally, this article points the challenges of HEO anodes, including low reversible capacity, low initial coulombic efficiency, and unclear reaction mechanisms. In the future, the researchers should focus on computational modeling, machine learning, and advanced in situ characterization to explore the next-generation HEO anodes for LIBs.

The extreme atmospheric persistence of sulfur hexafluoride (SF₆), coupled with its high global warming potential, necessitates effective degradation strategies. Herein, we report a reduction-precipitation platform that simultaneously achieves SF₆ defluorination and in situ fluoride immobilization. Hydrated electrons ($$) generated via photoreduction drive the cleavage of SF bonds, achieving enhanced SF₆ degradation. Crucially, in situ precipitation with calcium salts directly converts the released fluoride ions into fluorite (CaF₂), eliminating secondary pollution. XRD analysis confirmed complete phase transformation to pure CaF₂ within 24 h using either Ca(OH)₂ or CaCl₂ as the calcium source, with fluoride mineralization efficiency exceeding 98%. This integrated approach of reduction and mineralization offers a new solution for managing SF₆ and may offer insights for the degradation of other fluorinated greenhouse gases.

Organic redox-active electrode materials are gaining increasing attention due to their eco-friendliness, abundance, and structural versatility. However, their processing typically depends on poly(vinylidene difluoride) (PVdF) as binder and N-methyl-2-pyrrolidone (NMP) as solvent, both are expensive and hazardous. While aqueous processing methods are well established for inorganic electrodes, their application to organic materials remains largely unexplored. This study investigates the use of water-processable binders, specifically sodium carboxymethyl cellulose (Na-CMC) and styrene-butadiene rubber (SBR) for fabricating poly(3-vinyl-N-methylphenothiazine) electrodes. Key factors influencing electrode performance and microstructure were systematically studied, including the choice of conductive additive, mixing procedures, hot-pressing, and densification. Among these, the selection of conductive additive, mixing method, and room temperature densification at different pressure had the most pronounced impact on electrochemical performance. Electrodes using Na-CMC as the primary binder retained ≈90% of their theoretical capacity over 1000 cycles at 1C rate, comparable to PVdF-based electrodes. While increased densification pressure improved electrode uniformity, it had a detrimental effect on electrochemical performance. Introducing SBR as a co-binder at various weight ratios enhanced mechanical integrity and mitigated the negative effects of high densification pressure, ultimately leading to improved electrochemical performance under these applied operation conditions.