ChemSusChem最新文献

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.

Developing highly efficient, stable, and low-cost nonprecious metal electrocatalysts for the hydrogen evolution reaction (HER) is critical for scalable green hydrogen production. Herein, we designed a powerful metal ion intercalation strategy to fabricate high-performance MXene-based HER catalysts. Systematic studies on Mo₂TiC₂T_x (T_x= O, OH, F) intercalated with Co²⁺, Mn²⁺, and Ni²⁺ ions reveal that all three intercalants could induce interlayer expansion to expose active sites. Further in-depth investigation reveals that the incorporation of Ni²⁺ in the Mo₂TiC₂T_x forms NiOMo bonds, creating a strong electronic interaction that drives charge transfer from Ni atoms to Mo and O atoms. This results in an electron-rich Mo₂TiC₂T_x surface, thereby enhancing its catalytic activity. As a result, the optimal 1 mM Ni²⁺-Mo₂TiC₂T_x catalyst yields exceptional HER performance in 0.5 M H₂SO₄, requiring an overpotential of only 93 mV to achieve 10 mA cm⁻² and demonstrating remarkable stability over 700 h of continuous operation, which confirms its high activity and excellent durability. This article proposes an innovative strategy for designing MXene-based catalysts through the synergistic control of interlayer spacing and electronic structure.

Catalytic pyrolysis is an effective approach to enhance the quality of microalgal pyrolytic oil, and activated carbon (AC) catalysts have garnered extensive attention. However, the evolution mechanism of products with AC catalysis remains unclear, which is crucial for the subsequent utilization of this technology. In this study, the evolution mechanism and N, O conversion pathways of microalgae catalytic pyrolysis with AC were explored through model compounds (lipids, protein, and carbohydrate), and the formation mechanism of aromatics (especially BTEX) was also discussed. It was found that AC catalysis might effectively promote water-gas reaction and reduce the water yield, and obviously accelerate decarboxylation of acid from lipid as well as dehydroxylation, decarbonylation and ring-opening of furfural from carbohydrates. For N-compounds, AC catalysis might facilitate the deamination of amides/amines and the ring-opening reaction and denitrification of unstable N-heterocycles. Moreover, nitrogen-containing groups underwent oxidation to form N_xO_y with AC catalysis. Consequently, the contents of oxygen and nitrogen in the oil decreased under AC catalysis, and the high calorific value gas products rich in C₂₊ and CO were obtained. Besides, AC catalysis increased the yield of aromatics, the BTEX from microalgae primarily derived from lipid and protein.

Recent advances in biocatalytic recycling of polyethylene terephthalate (PET) using PET hydrolase enzymes have sparked interest in integrating PET degradation capabilities into living systems. Although cell-based strategies are limited by the mesophilic temperature constraints of microbial hosts, they offer a unique opportunity to couple PET depolymerization with biological upcycling into value-added chemicals. Here, a comprehensive approach for the cellular degradation and valorization of PET is reported. The crystal structure of MG8, a PET hydrolase identified from the human saliva metagenome is solved, and molecular dynamics simulations are used to pinpoint loop regions for targeted mutagenesis aimed at enhancing activity under moderate temperatures. Over 1000 MG8 loop variants are evaluated with a high-throughput mass spectrometric screening platform. Two catalytically improved mutants—MG8^G127Y/F250A and MG8^{N125S/G127Y/F250A}—exhibit significantly enhanced PET hydrolysis at 37°C. To enable whole-cell PET valorization, a two-strain Escherichia coli system called PETCAT is constructed: one strain is engineered to secrete MG8^G127Y/F250A for PET degradation, and the other harbors a synthetic pathway comprising seven heterologous genes for the conversion of terephthalic acid (TPA) into catechol, a versatile intermediate used in pharmaceuticals and fragrances. This study establishes a modular, one-pot microbial platform for PET recycling and upcycling under physiologically relevant conditions.

Indirubin, the active component of the traditional Chinese remedy Dang Gui Long Hui Wan, exhibits broad therapeutic potential. However, its scalable and sustainable synthesis remains challenging when using conventional methods. We report a green and efficient synthetic protocol using deep eutectic solvents (DESs) as environmentally benign media. Indirubin was synthesized from isatin using NaBH₄ in a choline chloride/urea DES at 70°C under air, achieving a 70% overall yield in 24 h without chromatographic purification. This approach, combined with an optimized work-up, significantly reduces organic solvent use, improving both process safety and environmental sustainability. The protocol is robust and scalable, as demonstrated by a pilot-scale preparation (386 g of isatin in 1.94 kg of DES), and grants access to a variety of indirubin derivatives, such as 5,5′-difluoro, 5,5′-dibromo, 5,5′-dimethoxy, 5,5′-dimethyl, 5-bromoindirubin, 3′-oxime, and N-alkylated analogs, the latter being of particular interest as photoswitchable molecular platforms. A comprehensive CHEM21 metrics assessment reveals a 3.7-fold reduction in E-factor and improved effective mass yield (EM) and process mass intensity (PMI) values compared to conventional methanol-based methods, underscoring the reduced environmental footprint of this approach. Overall, this strategy provides a greener, safer, and industrially viable route to pharmaceutically relevant indirubin scaffolds, fully aligned with sustainable chemistry principles.