ChemSusChem最新文献

Electrocatalytic CO₂ reduction (ECO₂R) to high-value chemicals is a promising method to upcycle emitted CO₂, but it is also a fascinating scientific challenge. Catalyst materials, as well as cell configurations, play a pivotal role in the efficacy and efficiency of the ECO₂R reaction, which also dictates reaction pathways and product selectivity. In this work, we employ the isotopological Zr- and Ce-based UiO-67 metal–organic frameworks (MOFs) that contain Pd species in a zero-gap gas diffusion cathode electrode configuration, where the water content, i.e., relative humidity (RH) level, in the CO₂ gas stream can be varied. We show that only UiO-67-based MOFs containing Pd embedded in their pores can produce syngas, while the product selectivity can be controlled by varying the RH levels in the gas stream. The pristine MOFs (precatalysts) undergo chemical and structural transformation during the ECO₂R reaction, forming the active catalysts toward CO₂ electroreduction to syngas. Our work highlights the effect of water content on the selectivity during ECO₂R, but also the need for predictive catalyst design for effective electroreduction of CO₂ to high-value chemicals.

Nonthermal plasma (NTP)-assisted ammonia synthesis is an emerging catalytic method using plasma technology to activate reactants. It can operate at room temperature and atmospheric pressure, significantly boosting reaction activity and improving ammonia synthesis efficiency. However, standalone plasma systems still face limitations ammonia yield and energy efficiency, highlighting the need for synergistic effects from efficient catalysts to improve overall performance. In this study, a CoNi bimetallic catalyst supported on SBA-15 was designed and synthesized to optimize metal dispersion, increase the exposure of active surface sites, and enhance plasma activation efficiency. SBA-15 was synthesized hydrothermally, and Co and Ni were loaded by impregnation to obtain high-performance catalysts. Under room temperature and atmospheric pressure, the plasma-assisted ammonia synthesis achieved a yield of 228 μmol/(min·g_-cat). Comprehensive structural and surface characterizations (SEM, TEM, XRD, BET, NH₃-TPD, and XPS) revealed that the incorporation of Co significantly improved the dispersion of Ni, reduced the metal particle size, and strengthened the interaction between the metal and the support. These improvements contributed to enhanced adsorption and activation of reactive intermediates. This work provides insights into the design of efficient bimetallic catalysts for plasma-assisted ammonia synthesis and contributes to sustainable nitrogen utilization within the framework of a circular nitrogen economy.

Artificial photosynthesis using earth abundant resources water and oxygen to give a green oxidant hydrogen peroxide (H₂O₂) has drawn extensive attention. Targeted designing photocatalysts for efficient H₂O₂ synthesis remains a fundamental and technological challenge. In this regard, thiophene-derived structural motifs with unique conjugation systems and electron-rich properties often serve as building blocks for synthesis of metal-free porous organic semiconductors (POSs). These semiconductors have advantages for instance broad light absorption range, efficient charge separation and transfer, superior mass transportation, and good stability, along with flexible synthesis and functionalization, which exhibit excellent performance in H₂O₂ photosynthesis. This review summarizes the recent key advances in the synthesis of thiophene-derived POSs and their applications for H₂O₂ synthesis, which poses the current bottlenecks in this area. A general perspective on the future effort on this topic is provided.

In this work, we investigated the pyrolysis of sinapic acid (SA) as a lignin S-units model compound on the nanoceria catalyst. We employed various techniques to unravel the pyrolysis mechanism, including temperature-programmed desorption mass spectrometry, thermogravimetric, and IR spectroscopic techniques, complemented with atomistic simulations. From spectroscopic data and atomistic models, we report that SA interacts with the catalyst via its carboxyl group and aromatic functional groups; the amounts of various surface complexes depend on the acid concentration. Conformational analysis revealed that parallel adsorption on ceria was preferred over the perpendicular one (ΔE₀ = −154 kJ mol⁻¹). The main pyrolysis products are associated with transformations of phenolate complexes, with the predominant formation of syringol and with decarboxylation of carboxylates, forming 4-vinyl syringol, well known as canolol, thanks to its exceptional antioxidant properties. Modeling the transition state between the SA and its vinyl analog, canolol, displayed an additional intramolecular decarboxylation pathway with an activation energy barrier of +189 kJ mol⁻¹. This is consistent with the activation energy E^≠ = 194 kJ mol⁻¹ calculated from experimental kinetic data, and complements other established decarboxylation pathways. Methyl-syringol, cresol, phenol, toluene, benzene, and other aromatics were found among the catalytic pyrolysis products of SA.

The increasing environmental impact of conventional petroleum-based or nondegradable plastics has prompted the development of compostable alternatives that can be safely degraded within managed organic waste management systems. Compostable plastics, a type of biodegradable plastic, are specifically designed to degrade under aerobic conditions without producing toxic residues or degrading compost quality. This review provides a comprehensive overview of compostable plastics, focusing on international standards, degradation mechanisms, compatibility with composting systems, and recently developed materials. Key compostability criteria such as biodegradability, degradability, nontoxicity, and neutral impact on compost quality are discussed in the context of certification schemes such as EN 13 432, ASTM D6400, and ISO 17 088. Notable studies on representative compostable plastics, including polylactic acid (PLA), polyhydroxyalkanoates (PHA), polybutylene succinate (PBS), starch-based plastics, and polybutylene adipate terephthalate (PBAT), are also reviewed.

Lithium-sulfur (Li-S) batteries face two key challenges including the detrimental “shuttle effect” of long-chain lithium polysulfides (LiPSs, Li₂S_n, 4 ≤ n ≤ 8) and the slow conversion kinetics from Li₂S₄ to Li₂S. To address this, we developed a bidirectional catalyst featuring Ni/NiSe heterojunctions encapsulated within nitrogen-doped carbon nanotubes (NCNT) via an in situ CNT-encapsulation strategy to promote the conversion of sulfur species. The abundant heterointerfaces in Ni/NiSe@NCNT provide multiple active sites, which not only strongly adsorb LiPSs via chemical interactions but also serve as bidirectional catalyst to enhance the sulfur reduction reaction. In situ Raman spectroscopy and electrochemical analysis both confirmed that the Ni/NiSe@NCNT catalyst effectively suppresses the LiPSs shuttle effect and enhanced the redox reaction kinetics of sulfur. The batteries with this modified separator exhibit outstanding performance with a discharge capacity of 1406.2 mAh g⁻¹ at 0.1C and robust cycling stability. Furthermore, under demanding conditions of high sulfur loading (6.78 mg cm⁻²) and low electrolyte/sulfur ratio, the cell delivers a reversible specific capacity of 589.9 mAh g⁻¹. This work provides new insights into the catalytic role of transition metals in sulfur reduction reaction and proposes an effective strategy for designing stable, high-performance bidirectional catalysts for Li-S batteries.

An all-uranium-based electrochemical cell consisting of simple [U^IV/V(^tBuacac)₄]^0/+ and [U^III/IV(N(SiMe₃)₂)₄]^−/0 complexes as anolyte and catholyte species was constructed with a cell voltage of 2.2 V. The [U^IV(^tBuacac)₄] (1) and [U^IV(N(SiMe₃)₂)₄] (2) complexes have favorable properties for redox-flow-battery applications, including reversible redox chemistry, relatively high stability toward electrochemical cycling, and high solubility in common organic solvents. The [U^III/IV(N(SiMe₃)₂)₄]^−/0 complexes were first isolated and characterized by Schelter et al., and performed well in electrochemical studies due to the comparably low reduction potential of −2.05 V vs. Fc/Fc⁺ to the reduced uranium(III) species. Treatment of conveniently accessible 1 with AgSbF₆ allowed the isolation of [U^V(^tBuacac)₄][SbF₆] (3), which is the active catholyte species generated during cell charging. Galvanostatic cycling with charging and discharging at currents of 20 and 5 μA, respectively, was performed in a two-compartment static H-cell with high-surface-area carbon fiber electrodes to achieve a potential of 2.2 V. The success of this 1||2 cell-provides a promising entry point to a potential future class of uranium-based, nonaqueous redox-flow-battery electrolytes, not for use in personal devices but incorporated into underground energy storage systems, where weight and radioactivity levels are not an issue and where this abundant waste material could find new application.

The interfacial properties of the hole transport layer (HTL) are absolutely critical for perovskite solar cells (PSCs) nowadays. [4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) is widely used HTL within the class of self-assembled materials. However, during its self-assembly process, Me-4PACz tends to form molecular clusters and micelles on indium tin oxide (ITO), leading to insufficient coverage. Therefore, we propose a co-assembled monolayer (Co-SAM) strategy via co-depositing phenylphosphonic acid (PPA) or its derivatives as co-dopants with Me-4PACz, the intermolecular steric hindrance between phenyl and carbazole groups effectively suppresses Me-4PACz aggregation. Simultaneously, the phosphonic acid groups of both molecules form a synergistic dual-anchoring effect, significantly enhancing HTL uniformity and coverage. Furthermore, active substituents (-OH, -NH₂, -Br) in the dopants can passivate uncoordinated Pb²⁺ ions and iodine vacancies at the perovskite interface, thereby optimizing the HTL/perovskite contact and improving carrier extraction ability. Results show that inverted devices based on Me-4PACz+BrPPA Co-SAM achieve a power conversion efficiency (PCE) of 23.73%, representing a substantial increase from 21.39% while maintaining excellent stability. This strategy provides a new direction for developing high-performance Co-SAM and advancing the industrialization of PSCs.

The practical application of the sulfur cathode in lithium–sulfur (Li–S) batteries mainly depends on the suppression of lithium polysulfide (LiPSs) diffusion and the improvement of its kinetics. Efficient 2D adsorption-catalytic media are an important direction for its future progress. Herein, the ultrathin (~2.2 nm) Fe₂O₃-Fe₃O₄ heterointerface is rapidly synthesized. As an adsorption and catalytic medium for LiPSs, it exhibits a stronger LiPS affinity than the single-component Fe₃O₄ and Fe₂O₃. The built-in electric field at the heterogeneous interface can significantly enhance the kinetics of charge transfer. It provides a positive regulatory effect on the smooth “adsorption-migration-conversion” process of active sulfur species. Both theoretical calculations and in situ Raman have verified its performance enhancement mechanism. As a result, the cell based on this heterointerface achieves reversible capacities of up to 737 mAh·g⁻¹ at 4 C. A high capacity retention of 493 mAh·g⁻¹ is maintained after 500 cycles at 2 C. Even under a high sulfur load of 4.2 mg·cm⁻², an area capacity of 6.1 mAh·cm⁻² can still be obtained, with stable cycling maintained for dozens of cycles.

Designing efficient and durable electrocatalysts for alkaline hydrogen evolution reaction (HER) is pivotal to a sustainable hydrogen economy. Here, we embed ultrafine RuIr alloy nanoparticles in N-doped porous carbon nanofibers (NCNFs) by electrospinning energetic metal-organic framework (MOF) precursors followed by pyrolysis. The resulting RuIr@NCNFs exhibit an overpotential as low as 22 mV at 10 mA cm^-2 in 1.0 M KOH, surpassing commercial Pt/C, and exhibit negligible activity decay over 12 h of continuous operation. Combined density functional theory and spectroscopy indicate Ir → Ru charge redistribution that optimizes ΔG_{H *} and facilitates water dissociation (Volmer), thereby accelerating the overall alkaline HER kinetics. Meanwhile, Ir incorporation mitigates Ru oxidation, enhancing long-term durability. Additionally, the N-doped porous carbon scaffold enhances electronic conductivity and mass transport, further boosting performance. This work highlights how bimetallic synergy coupled with MOF-derived carbon architectures enables highly active and robust alkaline HER catalysts with technologically relevant durability.