ChemSusChem最新文献

Ring-opening (co)polymerization is a versatile method for the synthesis of aliphatic polyesters. A fundamental challenge in this field lies in devising fresh synthetic methodologies to broaden the scope of aliphatic polyesters. In this study, we have successfully achieved the cationic copolymerization of various oxetanes (OX) and cyclic anhydrides using diverse Lewis/Bronsted acid catalysts. The method yields aliphatic polyesters with various structures and properties. It is proposed that OX firstly self-polymerized rapidly to form polyether, which then converted into polyester via the chain transfer reaction from polyether to cyclic anhydride. The resulting polyesters exhibit low number-average molecular weights (M_ns) of 1.7–4.8 kDa, dispersities (Ð) of 1.1–1.6, glass transition temperatures (T_gs) ranging from −55 to 2 °C, and high decomposition temperatures (T_ds) of up to 339 °C. This study has introduced a practical approach for synthesizing aliphatic polyesters through cationic copolymerization.

Developing catalyst-free photochemical transformations that efficiently harness visible light remains an important challenge in sustainable organic synthesis. Herein, we report a visible-light-induced decarboxylative C─C coupling of readily available cinnamic acids with aryl diazonium salts for the stereoselective synthesis of stilbene derivatives. The reaction proceeds under transition-metal- and photosensitizer-free conditions using ethanol as a green solvent and K₂CO₃ as an inexpensive base, providing a broad range of stilbenes in good to excellent yields with excellent E-selectivity. Remarkably, simply changing the irradiation wavelength enables access to the corresponding Z-stilbenes as the major stereoisomer, providing a convenient wavelength-controlled stereodivergent protocol. The synthetic utility is further enhanced by gram-scale synthesis and chromatographic purification-free product isolation through simple recrystallization. Experimental studies combined with DFT calculations support an electron donor–acceptor (EDA)-complex-mediated photoinduced single-electron-transfer process that generates alkenyl and aryl radicals for subsequent radical–radical coupling. This work demonstrates the potential of EDA-complex photochemistry as a practical and sustainable platform for catalyst-free C─C bond formation.

The massive accumulation of polyethylene terephthalate (PET) waste necessitates efficient recycling technologies to mitigate environmental pollution. Chemical depolymerization converts PET into high-purity monomers, offering a promising route for closed-loop plastic circularity. This review systematically summarizes recent advances in catalytic PET depolymerization, emphasizing reaction mechanisms, catalyst design, and process intensification. We analyze major depolymerization routes, namely hydrolysis, methanolysis, glycolysis, and aminolysis while highlighting fundamental mechanistic insights such as nucleophilic transesterification and emerging β-cleavage pathways. Furthermore, we evaluate catalyst design principles for active sites (e.g., Brønsted and Lewis acids, bridged bimetallic centers, and defect-engineered structures) across various homogeneous and heterogeneous systems, including ionic liquids, metal-organic frameworks, and zeolites. Finally, we highlight recent progress in process intensification strategies, such as interfacial catalysis, microwave-assisted reactions, and tandem one-pot processes. By integrating mechanistic understanding with catalyst engineering, this review provides a comprehensive perspective and outlines future directions for sustainable, industrially viable closed-loop PET recycling.

Achieving both high catalytic activity and durable long-term stability remains a key challenge for efficient water splitting across a wide pH range. Although RuO₂ is decidedly active for the oxygen evolution reaction (OER), its stability is compromised by over-oxidation and dissolution under harsh conditions. In this study, we engineered carbon nitride (CN_x) doped ruthenium molybdenum mixed oxide (RuO₂–MoO₃/CN_x) which exhibits excellent bifunctional electrocatalytic performance toward both HER and OER in acidic and alkaline media. In 1 M KOH, it delivers low overpotentials of 19 mV for HER and 250 mV for OER at a current density of 10 mA/cm². Notably, the catalyst also maintains appreciable activity under acidic conditions. The superior performance of RuO₂–MoO₃/CN_x originates from oxygen spillover at the RuO₂–MoO₃ interface, where reactive oxygen species migrate to MoO₃, suppressing over-oxidation of Ru active sites and enhancing durability. Concurrently, strong interfacial electronic interactions optimize adsorption of reaction intermediates and accelerate kinetics. Together with high surface area, efficient mass and electron transport, these features enable excellent catalytic activity across both acidic and alkaline media, providing an effective strategy for the design of robust electrocatalysts for green and renewable energy conversion.

Conversion of cellulose for the production of furanics and levulinates presents a significant opportunity to improve biomass valorization, highlighting a potential area for industrial innovation. However, the catalytic production of furfural from celulosic biomass has diverse applications in the chemical and energy sectors. But, it presents significant challenges in terms of selectivity and efficiency. In this regard, the study outlines existing challenges and highlights recent advancements in the production of furfural from cellulosic biomass. The study emphasizes the efficient utilization of cellulose, which constitutes a larger portion of lignocellulosic biomass, to enhance furfural yield and overall biomass valorization, representing a vital area for future research and industrial advancement. This review aims to address advances in catalyst design, solvent systems, and reaction engineering, alongside mechanistic insights into the transformation of hexose sugars into furfural. By integrating these perspectives, the review identifies strategic opportunities to overcome selectivity barriers and scale sustainable furfural production from cellulose-rich feedstocks.

A series of Ag@NiX composite photocatalysts were successfully constructed via a chemical reduction strategy and applied to gas-solid phase photocatalytic CO₂ reduction without additional photosensitizer using H₂O as sacrificial agent. The introduction of Ag nanoparticles (Ag NPs) on a Ni-MOF, namely [Ni₂(tipe)(cca)₂(H₂O)₂] ·2DMF·2H₂O (NiX) (tipe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethene, H₂cca = 4-carboxycinnamic acid), effectively enhanced visible-light absorption capability of the composites and promoted separation and migration of photogenerated charge carriers. Among the prepared samples, Ag@NiX-2 exhibited optimal photocatalytic performance and achieved a CO production rate of 14.7 μmol g⁻¹ in 5 h. In situ FT-IR measurements revealed the formation of key intermediate *COOH during the CO₂ photoreduction process, thereby elucidating the reaction pathway. Theoretical calculations showed that an interfacial charge transfer occurs between Ag NPs and NiX in the Ag@NiX composite, thus reducing the reaction Gibbs free energy. This study offers a feasible approach for rational development of MOF-based composite photocatalysts toward efficient photocatalytic CO₂ reduction.

In this work, novel CS-630/xSBGO composites were synthesized by anchoring three-dimensional (3D) CoS₂ (CS-630) nanoparticles directly onto spent battery-derived graphene oxide (SBGO) nanosheets through a facile pyrolysis process, forming an integrated conductive SBGO-supported structure. The resulting CS-630/xSBGO composites were systematically evaluated as an electrocatalyst for hydrogen evolution reaction (HER) in acidic electrolyte. Among the investigated compositions, the optimized CS-630/0.2SBGO (1:0.2 w/w) catalyst demonstrated outstanding HER performance in 0.5 M H₂SO₄, requiring only 170 mV to reach 10 mA cm⁻², with a Tafel slope of 48 mV dec⁻¹ and an exchange current density of 0.0178 mA cm⁻². This improved performance arises from the abundant heterointerfaces between CS-630 and SBGO, which modulate the electronic structure, promote charge transfer, and accelerate the kinetics of water adsorption and dissociation. In addition, the conductive SBGO matrix provides a sustainable platform that highlights a waste-to-resource strategy for energy conversion. The catalyst also demonstrates stable HER performance in real water samples with a Faradaic efficiency of 95% under acidic conditions. Density functional theory calculations reveal pronounced electronic coupling and charge redistribution at the CoS₂–SBGO interface, which modulate the local electronic environment of the active sites and may contribute to the enhanced HER activity.

Waste plastic valorization has become a critical challenge in achieving global circular economy goals and mitigating climate change. However, the field suffers from fundamental inconsistencies in terminology and classification that impede scientific communication, technology development, and policy formulation. This study critically analyzes existing classification frameworks for waste plastic valorization technologies and identifies major sources of confusion: (i) ambiguous classification of dissolution processes across physical and chemical recycling categories; (ii) conflation of dissolution with chemical depolymerization despite their distinct mechanisms and products; (iii) inconsistent definitions of pyrolysis and gasification that blur the distinction between fundamentally different thermochemical processes; (iv) arbitrary temperature-based subcategorization of pyrolysis lacking scientific basis; and (v) misleading designation of energy recovery as “thermal recycling.” I propose a coherent classification scheme based on process-type logic: dissolution is repositioned within chemical recycling based on its operational characteristics, chemical recycling and feedstock recycling are explicitly differentiated, and energy recovery is divided into direct (combustion of waste plastic) and indirect (combustion of thermochemically-derived fuels) pathways. This unified framework aims to establish a common foundation for education, research, and evidence-based policymaking in sustainable waste plastic management.

The catalytic oxidation of poly(ethylene-co-vinyl alcohol) (EVOH) into oxygenated organic compounds such as carboxylic acids and aldehydes offers a promising approach to enhance the recyclability of multilayer plastic films. While EVOH provides oxygen barrier properties, its immiscibility with polyolefins in the melt phase limits physical recycling routes. A potentially low-cost option to increase multilayer plastic recycling is to selectively remove the more labile EVOH layer via oxidation while preserving the polyolefin content, which typically constitutes the majority of the film. In this study, we investigate the oxidation of EVOH using metal oxide catalysts under mild thermal conditions. Among catalyst candidates, CeO₂ exhibited the highest activity, consistent with its low oxygen vacancy formation energy, high oxygen storage capacity, and redox-active Ce³⁺/Ce⁴⁺ pairs. Product analysis revealed the formation of a broad range of oxygenated compounds, including carboxylic acids, aldehydes, and ketones, demonstrating oxidative C─C bond cleavage. While EVOH conversion was limited by incomplete mixing and catalyst deactivation, the results demonstrate the potential of CeO₂-catalyzed oxidation for selective removal of EVOH as a recycling approach, which is aligned with circular economy principles.

The structural versatility of metal–organic frameworks (MOFs) makes them attractive platforms for electrocatalyst design, but with limited active site density. Here, Fe-MOF is decorated with Ni-, Mo-, and W-based oxides via electrochemical deposition, avoiding high-temperature carbonization. The short interlayer distances (1.88–2.67 Å) and more negative binding energies (−4.09 to −4.88 eV) indicate intimate interfacial contact and strong adhesion between the deposited metal oxides and the Fe-MOF. Synergistic interactions between Ni 3d and Mo/W non‑3d orbitals modulate electronic structure and optimize adsorption of reaction intermediates. Electron localization values <0.5 and charge density difference analysis reveal substantial electron redistribution and interfacial charge transfer. DFT studies show that NiMoW@Fe-MOF with the lowest ɳ_OER (0.68 V) preferentially adsorbs OH⁻ over Cl⁻ (−1.14 and −1.09 eV, respectively), promoting selective OER. The NiW@Fe-MOF (cathode) exhibits the most favorable ΔG_H* (−1.64 eV) and suppresses Ca(OH)₂ and Mg(OH)₂ precipitation via WO₂-mediated OH⁻ consumption. Consequently, the NiW@Fe-MOF‖NiMoW@Fe-MOF enables selective inhibition of chlorine evolution and mitigation of scaling. The NiW@Fe-MOF‖NiMoW@Fe-MOF operates stably in alkaline seawater at 0.5 A cm⁻² for 500 h and delivers 1 A cm⁻² at 1.84 V, well below the 2.35 V required by a 20% Pt/C‖RuO₂ benchmark, demonstrating strong potential for direct seawater splitting.