ChemSusChem最新文献

Supercapacitors (SCs) are high-power energy storage devices but often experience reduced electrochemical performance at low temperatures, especially below -30 °C, due to the high freezing points of conventional electrolytes. In this study, we introduce a novel high-entropy electrolyte (HEE) for supercapacitors that extends operational capabilities over a wide temperature range. The high entropy of the HEE results in an exceptionally low freezing point of -116 °C. With an increased number of solvent molecules in the cation solvation structures, the HEE exhibits high conductivity (3.9 mS cm⁻¹ at -50 °C) and low de-solvation energy (14.1 kJ mol⁻¹). When incorporated into a carbon-based SC, the HEE enables a capacitance retention of 58% at temperatures below -30 °C, compared to 25 °C, while conventional single-solvent electrolytes retain only 38%. Additionally, the HEE provides superior high-rate performance and excellent cycling stability, maintaining 88% capacitance after 15,000 cycles, compared to 73% with conventional electrolytes.

Three cobalt-based metal-organic framework (MOF)-derived catalysts were developed for photothermal hydrogen production via ammonia decomposition. The selected MOFs were from distinct families, featuring carboxylate and imidazole linkers, and diverse in terms of porosity. The resulting catalysts consisted of uniform and homogeneously dispersed cobalt nanoparticles embedded within a carbon matrix. The carboxylate-based MOF-74 derived catalyst showed the highest initial activity, but gradually deactivated. ZIF-67 derived catalyst, however, demonstrated stable performance. The synergy between photo and thermal effects was confirmed. Additionally, this catalyst was found to be also effective in ammonia synthesis, potentially closing the loop for sustainable ammonia utilization.

Poly(heptazine imide) (PHI) has received widely interest in the photocatalytic CO2 reduction due to its good crystallinity and complete in-plane structure. However, its poor photo-induced carrier separation and migration efficiency and insufficient active sites results in undesirable photocatalytic CO2 reduction performance. Herein, we designed and constructed a novel ohmic junction photocatalyst by integrating melamine edge-modified PHI (mel-PHI) with extended π-conjugated system with TiN (TiN/mel-PHI) for enhancing the photocatalytic CO2 reduction activity. Strikingly, the photocayalytic CO2 reduction yield of the optimal TiN/mel-PHI is 62.64 µmol·g-1·h-1, which is 5.6 and 2.8 times higher than PHI (11.26 µmol·g-1·h-1) and mel-PHI (22.32 µmol·g-1·h-1), respectively. The superior photocatalytic CO2 reduction activity is attributed not only to the formation of D-A structure by the introduction of melamine, which extends the π-conjugation system, alters the electronic structure of PHI, and accelerates the charge separation and migration, but also to the induced internal electric field by ohmic junction further enhances the charge separation and migration efficiency. Meanwhile, the synergistic effect of mel-PHI and TiN enriched the electron number of TiN, reducing the CO2 reduction potential. This work highlights the synergistic enhancement of charge transfer between D-A motifs and ohmic junctions, confirming their potential in optimizing photocatalysts.

Redox mediators (RMs) have shown promise in enhancing Li-O2 battery cycling stability by reducing overpotential. However, their application is hindered by the shuttle effect, leading to RM loss and Li anode corrosion. Here, we introduce a polyionic liquid, poly (1-Butyl-3-vinylimidazolium bis(trifluoromethanesulfonylimine)) ([PBVIm]- TFSI) as an additive, showcasing a novel Li anode protection strategy for LiI-mediated Li-O2 batteries. [PBVIm]+ cations migrate to the Li anode, forming a protective cationic shield that promotes uniform Li+ deposition. The addition of [PBVIm]-TFSI enhances the cycling stability, achieving 105 cycles at 200 mA·g-1, compared to the cell with LiI which exhibited 38 cycles under the same conditions. Synchrotron X-ray tomography reveals the evolution of this protective layer, providing insights into its formation mechanism, in conjunction with XPS analysis. Our findings offer a new approach to Li anode protection in Li-O2 batteries, emphasizing the critical role of interfacial engineering for battery performance.

This perspective focuses on the modulation of metal-support interaction (MSI) in catalysts for CO_x hydrogenation, highlighting their profound impact on catalytic performance. Firstly, it outlines different strategies, including the use of highly reducible oxides and moderate reduction treatments, which induce the classical strong metal-support interaction (SMSI) effect and the electronic metal-support interaction (EMSI) effect. Morphology engineering and crystalline phase manipulation of oxides presented as effective methods to control EMSI are also discussed. The discrimination of SMSI and EMSI can be achieved using oxides with low encapsulation tendencies, such as ZrO₂, which supports electronic modifications without or minimizing the overgrowth issues, optimizing the catalytic performance for methanation. Then, the synergy between Cu and ZnO in methanol synthesis, enhanced by SMSI, is emphasized inside. Optimizing support oxides to control oxygen vacancies enhances the catalytic performance of CO₂ hydrogenation to methanol. Perspectives for the future research on the fundamental understanding of structure-MSI-performance relationship for catalyst design is discussed.

Covalent organic frameworks (COFs) constitute an evolving class of permanently porous and ordered materials, and they have recently attracted increased interest due to their intriguing morphological features and numerous applications in gas storage, adsorption, and catalysis. However, their low aqueous stabilities and tedious syntheses generally hamper their use in heterogeneous catalysis. Nonetheless, a capable and water-stable heterogeneous catalytic system for coupling CO2/epoxides to generate industrially important cyclic carbonates is still of great interest. Herein, exceedingly water- and thermally stable 2D-cobalt-impregnated hydrazone-linked fibrous COFs are reported as a catalyst for CO2/epoxide coupling reactions at ambient pressure. The functionalized cobalt (Co)-doped COFs demonstrated excellent catalytic activities with the high TONs (80925) and TOFs (6466 h-1), outperforming reported heterogeneous catalysts for CO2/epoxide coupling at ambient pressure. We found that the Co2+ ions within the COF matrix catalyze CO2 cycloaddition through density functional theory calculations. We also confirmed the excellent structural stability and consistent activity of Co-doped COFs up to ten repeating cycles.

The study investigated the fouling propensity of polysulfone (PSF) hollow fiber (HF) mixed matrix membranes modified with 1.0 wt.% graphene oxide (GO). Using scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle (WCA), and mechanical assessments, the structural characteristics of both untreated and GO-modified PSF HF membranes were examined. Filtration experiments included pure water and model contaminants such as bovine serum albumin (BSA), humic acid (HA), E. coli, and oil-in-water emulsion. The GO-modified membranes demonstrated a significant enhancement in antifouling performance, recovering over 90% of their initial pure water flux with HA and oil, indicating high resistance to irreversible fouling. Additionally, the GO-modified membranes showed superior oil separation efficiency. However, fouling parameters for BSA were similar for both membrane types, suggesting that GO does not significantly affect membrane-BSA interactions. Both types of membranes displayed high retention capabilities for E. coli, with no noticeable improvement due to GO addition. This study highlights the potential of GO-modified PSF HF membranes in enhancing antifouling performance and oil separation efficiency.

The Front Cover shows visible-light-activated water splitting activated by graphitic carbon nitride supported on flexible carbon cloths and modified with nickel oxide cocatalysts. The photocatalytic activity was strongly dependent on the degree of NiO dispersion, the optimization of which yielded performances that compared favorably even with different benchmark systems based on IrO₂ and RuO₂. The system's stability and the activity retainment even in real seawater hold considerable promise for replacing noble-metal-based materials for various energy-related applications. More information can be found in the Research Article by D. Barreca and co-workers.

The rapid development of electric vehicles necessitates high-energy density Li-ion batteries for extended range. Silicon is a promising alternative to graphite anodes due to its high capacity; however, its substantial volume expansion during cycling leads to continuous growth of the solid electrolyte interphase and significant capacity fading. This study addresses these issues by designing a porous Si structure combined with a double carbon-species coating layer, induced by low interfacial energy in a scalable process. Carbon and graphene are located on Si surfaces, forming a close interface that maintains electrical contact, suppresses lithium consumption, and enhances charge transfer properties. The composite anode with a double carbon-species coating on Si demonstrates rapid stabilization with increasing coulombic efficiency, achieving a specific capacity of 1,814 mAh g-1 at 0.2 C and a high-rate capability of 1,356 mAh g-1 at 10C. Additionally, in a full-cell configuration with LiFePO4, it recorded a specific capacity of 161 mAh g-1 at 0.2 C. These results show the potential of porous Si with a carbon-graphene coating for stable, high-capacity operation in Li-ion batteries, offering new insights into high-performance electrochemical systems. Moreover, the double carbon-species coating derived from a scalable surface chemistry-based process presents a realistic alternative for industrial applications.

Plastic waste has caused severe global environmental pollution and health issues due to the high production rate and lack of proper disposal technology. Traditional methods to deal with plastic waste, such as incineration and landfilling, are deemed unsustainable and energy-intensive. A promising alternative is the photocatalytic conversion of plastic waste, using sunlight as a sustainable and carbon-neutral energy source to break down plastic waste under ambient pressure and low temperatures. This review aims to provide a comprehensive summary of recent advancements in plastic photoconversion, with an emphasis on the catalysts and reaction pathways. The mechanisms and reaction pathways are first summarized, followed by a detailed discussion of strategies to design catalysts for improved performance in photoconversion. Then, examples of photothermal degradation processes are presented. Finally, current strategies, challenges, and possible future directions of plastic photoconversion are summarized and discussed.