Catalysis Letters最新文献

A simple, convenient, environmentally friendly, and sustainable green protocol has been developed for the synthesis of biologically significant 5-substituted 1,2,4-triazolidine-3-thiones in excellent yields (72–97%). This green method involves a one-pot condensation between aldehydes or ketones with thiosemicarbazide at 70 °C, employing sustainable aqueous onion extract as a green catalyst in water as the reaction medium. A wide range of substrates, including aryl, heteroaryl, and aliphatic aldehydes or ketones, were efficiently transformed into the corresponding 1,2,4-triazolidine-3-thiones 3 or spiro 1,2,4-triazolidine-3-thiones 5 with high yields. Water, as a green solvent, enables the reaction to proceed smoothly while supporting a sustainable synthetic protocol. The present methodology aligns well with green chemistry principles by utilizing a biodegradable catalyst, an eco-friendly solvent, avoiding column chromatography, reducing reaction time, and achieving high yields with improved atom economy. Furthermore, in silico ADME profiling of all synthesized triazolidine-3-thione derivatives was performed using the SwissADME online tool to evaluate their drug-likeness, including BBB permeability, oral bioavailability, compliance with Lipinski’s rule of five, and synthetic accessibility. Among the synthesized compounds, the selected derivatives, such as 3a, 3c, 3d, 3q, and 5a, demonstrate a more balanced pharmacokinetic profile.

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Aqueous Onion Extract Catalyzed Sustainable and Green Synthesis of 5-Substituted 1,2,4-Triazolidine-3-thiones in Water and In silico ADME Evaluation

Single atom of transition metals (iron, cobalt, etc.) anchored on N-doped carbon materials (M-N-C) have become promising alternatives to Pt/C catalyst for oxygen reduction reaction (ORR) and proton exchange membrane fuel cells (PEMFC). Dual-atom catalysts (DACs) can further improve their performance due to the synergistic effect between two adjacent metal atoms, but the structure-activity relationship of the dual-metal-atom active site remains unclear, especially the impact of coordinated nitrogen species. Herein, we use a pre-carbonization and impregnation method to construct two different nitrogen coordinated Fe-Co dual-metal-atom active sites on carbon support. The existence of bimetallic dimer structure has been proved by HAADF-STEM and XAFS characterization. XPS results suggest that the pyridinic N and pyrrolic N content is different in two Fe-Co dual-atom catalysts. The experimental and theoretical ORR activity both suggest Fe-Co active site coordinated by pyridinic nitrogen is more favorable for ORR and PEMFC performance. Our work provides a deep insight into the relationship between the N species and activity of Fe-Co dual-metal-atom ORR catalysts.

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Dioxygen activation and catalysis around ambient temperature is a long-standing challenge in chemical industry. Inspired by the significant roles of hydrogen bond networks in dioxygen activation and catalysis by redox enzymes, here, we present a Lewis acid promoted dioxygen activation by manganese(II) complexes toward efficient organophosphine oxygenation (vs. enzymatic Brönsted acid (hydrogen bond)). The active species was assigned to the manganese(III) superoxo species, and its electrostatic interaction with Al³⁺, that is, LMn^III-O₂^−•···Al³⁺, sharply enhanced its electrophilicity for oxygenation.

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Effective utilization of lignocellulosic biomass as value-added fuels and chemicals is of great significance for achieving the dual goals of sustainable biorefinery and carbon neutrality. Here, Ni-WOx@C catalysts were synthesized for efficiently catalytic conversion of cellulose into ethylene glycol (EG). The catalyst was prepared through a one-step pyrolysis method by using citric acid and SiO₂ as the carbon source and structural template, respectively. A series of controlled experiments demonstrated that the pyrolysis temperature and the particle size of the SiO₂ template significantly affected the physicochemical properties of the catalyst, including the surface morphology, active sites provided by the loaded metals, and the distribution of Lewis acid sites. The optimized catalysts of Ni-WOx@C₆₀₀₋₂, which was prepared by the pyrolysis at 600 °C with a 2 μm SiO₂ template, delivered the best performance characterized by its high specific surface area (124.86 m²/g), well-defined pores, as well as the cooperation between metallic species and Lewis acid sites. Under the optimized reaction conditions (220 °C, 4 MPa H₂, 3 h), this as-prepared catalyst achieved nearly complete cellulose conversion (> 99%) and EG yield of 60.1%. Generally speaking, the design of Ni-WOx-based catalyst provides new insight for effective catalysis and has considerable application potential in cellulose conversion.

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Bismuth ferrite (BFO), a p-type semiconductor with notable visible-light absorption, is an attractive photocathode material for photoelectrochemical (PEC) systems. This study presents a facile route to construct BFO/ZnO heterojunctions on fluorine-doped tin oxide (FTO) substrates via sol-gel and scraping method. A comprehensive characterization of the samples, including surface morphology, crystal structure, and chemical states, confirmed the successful fabrication of the BFO/ZnO heterojunction. The pure BFO exhibits photocathode behavior, with a negative photocurrent of -7.0 µA/cm², consistent with its p-type semiconductor characteristic. All heterojunction samples exhibited enhanced PEC performance, as demonstrated by the higher photocurrent densities. A maximum photocurrent density of -24.6 µA/cm² was detected in the optimal BFO/ZnO heterojunction sample, which was 3.51 folds by that of the pure BFO. The enhancement of PEC properties can be attributed to the built-in electric field (E_bif) of the p-n junction, which can promote the separation and transfer efficiency of charge carriers, analyzed by the carrier dynamics and the well band alignment. This research offers a promising strategy for developing low-cost and efficient PEC conversion devices.

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This study establishes molecular design principles for bis(imino)pyridine cobalt catalysts to simultaneously enhance activity and 1-hexene selectivity in propylene oligomerization. Systematic substituent engineering revealed: (1) para-Halogenation (e.g., Br in 4d) boosts activity to high levels (4.68 × 10⁵ g/(mol_(Co)·h)) through electronic effects; (2) ortho-Steric modulation follows a volcano-shaped selectivity trend, with isopropyl groups optimizing 1-hexene formation; (3) Conversion control is critical for suppressing secondary reactions that compromise selectivity. Implementing these insights, catalyst 4L achieves 56.1% 1-hexene selectivity at low conversions (10.4%). These findings provide a blueprint for developing high-performance cobalt oligomerization catalysts through integrated electronic, steric, and process optimization.

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The innovation for highly effective solid acid catalysts that resist impurities is crucial for enhancing sustainable esterification and transesterification processes, which are vital for biofuel production and green chemistry. In this work, tungsten-modified sulfated titania (WO₃/SO₄²⁻/TiO₂) catalyst was prepared through the impregnation method and subsequently calcined at 550 °C to assess the impact of tungsten impurity on its structural and catalytic properties. The catalyst was characterized through FT-IR, XRD, NH₃-TPD, and BET surface area analysis. These analyses revealed that the presence of sulfate and tungsten species inhibited TiO₂ crystallization, improving the textural properties and increasing surface acidity. The 5 wt.% WO₃/SO₄²⁻/TiO₂ catalyst demonstrated the largest surface area (35.99 m²/g) and total acidity (1.20 mmol NH₃/g). This catalyst achieved 86.4% conversion in the reaction of transesterification of ethyl acetate and n-butanol at 100 °C for 3 h. The enhanced catalytic performance and selectivity were attributed to the synergistic interaction between WO₃ and SO₄²⁻, resulting in the formation of Lewis-Bronsted acid sites. This study provides important insights into how tungsten affects the structure and acidity of sulfated titania, which could guide the design of more efficient, impurity-tolerant solid acid catalysts for environmentally sustainable chemical processes.

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Isostearic acid, a bio-based and environmentally friendly chemical, has attracted considerable attention because of its high value as an oleic acid derivative. The synthesis of isostearic acid via oleic acid isomerization over commercial H-ZSM-5 zeolites is limited by low yield and acid value, mainly due to diffusion constraints. To address this issue, a hierarchical-pore H-ZSM-5 zeolite (Meso-5) was synthesized using Silicalite-1(S-1) as a seed crystal to enhance diffusion and catalytic performance. The catalyst was comprehensively characterized by XRD, SEM, BET, TGA, FT-IR, and Py-FTIR. Meso-5 efficiently catalyzed the isomerization of oleic acid, attributed to its abundant Brønsted and Lewis acid sites whose synergistic interaction significantly promoted the formation of branched-chain products. The catalyst delivered a selectivity of 87.3% with a 71.1% yield in the first run, and even after five reuse cycles it maintained 82.1% selectivity with a 55.6% yield. Evidently, the hierarchical pore structure of the catalyst significantly facilitated the diffusion of oleic acid molecules and their isomerized intermediates, thereby enhancing the overall catalytic activity. The resulting isostearic acid was purified via a simple recrystallization procedure to a purity of 83.4% and an acid value of 186.7 mg KOH/g, both meeting the standards of commercial isostearic acid. These findings provide a robust basis for further catalyst optimization and scale-up toward industrial isostearic acid production.

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A tandem catalytic route combining ZSM-5-driven isomerization with Ni/C-catalyzed hydrogenation enabled the efficient conversion of oleic acid to isostearic acid. The hierarchical H-ZSM-5 structure enhanced branched-chain formation, ensuring high selectivity and yield toward the desired product

The catalytic hydrogenation of CO₂ to light olefins remains limited by poor olefin selectivity and excessive methane formation. Here, we investigate the effect of dual alkali promotion on tuning the redox and electronic properties of Fe–Zn catalysts under mild reaction conditions. A series of Fe–Zn catalysts with controlled sodium to potassium ratios were prepared, and structural characterization confirmed that the ZnFe₂O₄ spinel phase was preserved across all samples. Notably, X-ray photoelectron spectroscopy indicates that co-promotion with sodium and potassium modifies the surface Fe³⁺/Fe²⁺ ratio beyond the trend observed in single-alkali systems, suggesting a cooperative electronic modulation. This cooperative effect is associated with enhanced CO₂ conversion pathways and suppressed deep hydrogenation. As a result, the balanced Na–K/Fe–Zn catalyst achieved the highest C₂–C₄ olefin selectivity (33.36%) while maintaining low methane formation (12.25%), among the investigated catalysts. A preliminary tandem coupling with HZSM-5 further illustrates the potential for downstream upgrading of in situ olefins into aromatics. Overall, these results highlight the potential of combined sodium and potassium promotion as an effective approach for enhancing light olefin production from CO₂ over Fe–Zn catalysts.

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The insufficient catalytic efficiency of non-noble metal materials in the alkaline hydrogen evolution reaction (HER) remains a critical challenge limiting their practical application. Herein, a W-modified NiSe₂-based catalyst (Ni-W-Se/NF) was in situ fabricated on nickel foam through a simple potentiostatic electrodeposition strategy. The incorporation of W effectively modulates the microstructure of NiSe₂-based catalysts, resulting in a significantly enlarged electrochemical active surface area for Ni-W-Se/NF. Benefiting from the synergistic effects of W-induced electronic modulation and morphology optimization, the Ni–W–Se/NF electrode exhibits enhanced HER performance in 1 M KOH, delivering a low overpotential of 64 mV at − 10 mA cm⁻². Moreover, the catalyst demonstrates good electrochemical durability, maintaining stable activity during continuous operation for 50 h. Overall, these findings highlight the potential of this catalyst as an economically viable cathode for alkaline water electrolysis.

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