Catalysis Letters最新文献

Phenolic wastewaters possess high toxicity and poor biodegradation and persist in ecosystem for longer periods, causing severe harm to living organisms. Thus, developing highly effective catalysis-oxidation system for phenolic wastewater treatment is highly needed. In this work, a high-performance magnetic cobalt carbocatalyst (M-Co/CN) was prepared via thermal pyrolysis of the amorphous cobalt-aspartic acid complex. It was further applied for activation of peroxymonosulfate (PMS) to degrade phenolic wastewaters. Related characterization results revealed that the compositions, structures, properties of the catalyst mainly depended on pyrolysis temperature. The formed porous CN layer at 600 ℃ could enhance adsorption and catalysis through improving mass transfer, restricting Co aggregation, and exposing more active sites. Therefore, the catalyst we prepared could show high catalytic performance in process of phenol wastewater treatment. Besides, reaction conditions (catalyst dosage, PMS dosage, phenol concentration, pH, and anion type, etc.) were further studied and optimized. Under the optimized conditions, a degradation efficiency of 95.0% was achieved for 100 ppm phenol within 1 h. Furthermore, radical quenching experiments and electron paramagnetic resonance spectroscopy jointly displayed that phenol degradation mechanism in the M-Co/CN-600-PMS system primarily involves the generation of singlet oxygen (¹O₂) with Co⁰ serving as active reaction sites. Besides, recycling experiment also demonstrated that M-Co/CN catalyst had high structure stability and better reusability after tests.

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In this study, we discuss the influence of carbon support on the performance of platinum nanoparticles (Pt-NPs) in gas-phase CO₂ hydrogenation towards industrially demanding CO production. To this end, Pt-supported on graphite oxide, carboHIPE, activated carbon, multiwalled carbon nanotubes (MWCNT), and graphite of different specific surface areas and degree of graphitization were synthesized with identical loading per unit surface area (25 µg Pt/m² of support) to reveal the contribution of the carbon support. All Pt@carbon nanocomposites were selective to CO at temperatures above 800 K, however, we found an additional correlation between their catalytic performance and the degree of graphitization of the support. Graphite-supported platinum (Pt@Graphite) has the highest TOF and the lowest activation energy among the studied nanocomposites due to the increasing electron donation from the carbon support to the Pt nanoparticles, which facilitates CO₂ adsorption on Pt by shifting its d-band centre towards the Fermi level. Our study shows that beside surface area, porosity, thermal stability, a further parameter needs to be taken into consideration, as the Pt/C interface has significant effect at the atomic level on the activity of carbon-supported catalysts in gas-phase CO₂ hydrogenation towards CO production.

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Environmental issues from petroleum-based plastics have intensified due to long-term accumulation. Their persistence harms marine and terrestrial life, disrupting food chains, and spreading microplastics. Increased plastic usage driven by industrialization, modern lifestyles, and disposable products contributes to this problem. An effective strategy to mitigate plastic’s negative impact includes waste reduction, recycling, and the development of biodegradable biopolymers. In this sense, polyhydroxyalkanoate (PHA) synthase (PhaC) is a vital enzyme for cost-effective biopolymer/bioplastic production. Thus, this study investigated four different genera (Azotobacter, Bacillus, Cupriavidus, and Halomonas) that are well-known PHA/Polyhydroxybutyrate (PHB) producers, selected due to their proven industrial capability and metabolic versatility in PHA/PHB biosynthesis. Since there has been inadequate information based on the three-dimensional (3D) structures of PHA synthase(s), this is the first report to assess the PHA synthase(s) of these indicated genera by conducting in silico comparative analyses on AlphaFold predicted structures. Furthermore, frustration analysis revealed structural similarities among Azotobacter, Cupriavidus, and Halomonas PHA synthases, while Bacillus exhibited a distinct profile. Identifying highly frustrated residues in potential substrate-binding regions offers insights into their functional dynamics and engineering potential. Molecular docking analysis was also performed to assess interactions between AlphaFold-predicted enzyme structures and their substrates, quantifying the binding energy of enzyme-substrate complexes. The findings of this work will contribute to the engineering of PHA synthase(s) of PHA/PHB producers with the simultaneous understanding of predicted 3D structures using the advanced capabilities of AlphaFold. This understanding will support the creation of more efficient and sustainable bioplastics for the future.

The composite materials of Pt-based catalysts and metal oxides have potential advantages in direct methanol fuel cells. However, synthesizing controllable Pt-based catalysts with high electrochemical properties is still challenging. In this paper, commercial Pt/C is improved by replacing commercial carbon black with carbon nanotubes and adding Ta₂O₅ cocatalyst. The particle size, structure, surface morphology, activity, and stability of the methanol oxidation reaction (MOR) of Pt/Ta₂O₅/MWCNTs composites were studied. The prepared Pt/Ta₂O₅/MWCNTs catalysts have higher catalytic activity and durability than commercial Pt/C in methanol electrooxidation reactions. In addition, when the loading of co-catalyst and Pt nanoparticles is adjusted, the catalyst with the loading of 20% Pt/MWCNTs/Ta₂O₅-15% has better electrochemical activity. This study shows that the Pt/ Ta₂O₅/MWCNTs catalyst should be a promising DMFC catalyst.

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Compared to traditional energy-intensive ammonia (NH₃) production methods, photocatalytic nitrogen (N₂) reduction offers significant energy savings. However, the complex kinetics and high reaction barriers have hindered its development. In this study, a novel Bi₂₄O₃₁Br₁₀/polyaniline (Bi₂₄O₃₁Br₁₀/PANI) composite photocatalyst was synthesized using a simple solvothermal and chemical oxidation polymerization method. Aniline was oxidized and deposited onto the surface of Bi₂₄O₃₁Br₁₀ nanosheets. The Bi₂₄O₃₁Br₁₀/PANI composite demonstrated better visible-light absorption, and more efficient transfer of photoexcited carriers than pure Bi₂₄O₃₁Br₁₀, resulting in superior photocatalytic N₂ fixation performance. The optimized Bi₂₄O₃₁Br₁₀/PANI composite attained an NH₃ production yield of 245.26 µmol g⁻¹ , approximately 7.0 times higher than pure Bi₂₄O₃₁Br₁₀. This study provides a new design of inorganic-polymer hybrid photocatalysts for efficient photocatalytic nitrogen fixation.

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The process of catalytically oxidizing carbon monoxide (CO) remains a critical issue across various industrial sectors. However, it continues to be a challenge to achieve effective CO oxidation at low temperatures using non-noble metal catalysts. This study addresses these gaps by investigating the effects of dilute gallium (Ga) doping on the catalytic performance of flower-like ceria (CeO₂) microspheres. By using a modified hydrothermal synthesis method, we prepared the Ga-doped CeO₂ microspheres and characterized their morphology, surface area, and evidence of oxygen vacancy through various experimental techniques as well as computational simulation method. Our findings disclosed that the incorporation of Ga significantly enhances the catalytic performance of CeO₂, with the optimal doping level (2 mol% Ga) achieving a 90% CO conversion temperature (T₉₀) of 388.9 °C, obviously lower than that of pristine CeO₂ (488.5 °C). This work demonstrates that dilute Ga doping effectively improves the catalytic properties of CeO₂-based materials, offering a potential strategy for developing effective CO oxidation catalysts.

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This study introduces an electrocatalyst composed of nickel-molybdenum-phosphide (NiMoP) supported on nickel foam (NiF), which has been synthesized using a straightforward two-step electrodeposition method intended for enhancing the efficiency of the hydrogen evolution reaction (HER) in alkaline environments. The addition of Mo and P, in contrast to traditional Ni-based catalysts, creates a synergistic electronic effect that considerably improves HER kinetics. The enhanced NiMoP/NiF catalyst demonstrates an impressively low overpotential of 171 mV at 10 mA cm⁻² and 376 mV at 100 mA․cm⁻², surpassing the performance of Ni/NiF (η₁₀ = 229 mV) and NiMo/NiF (η₁₀ = 181 mV). In comparison to current NiMoP systems, our catalyst exhibits superior catalytic activity, stability, and charge transfer efficiency. The electrochemical analysis indicates a Tafel slope of 119.98 mV․dec⁻¹, which supports a Volmer-controlled hydrogen evolution reaction mechanism characterized by enhanced water dissociation. The structural and compositional analysis demonstrates that Mo improves the electronic structure of Ni, whereas P increases water affinity and electrochemical surface area (C_dl = 3.18 mF·cm⁻²), which is almost four times higher than that of pristine NiF. The catalyst exhibits remarkable stability throughout 2000 cycles and shows reliable performance in multi-step chronopotentiometry evaluations. This study presents an economical, long-lasting, and scalable electrocatalyst for hydrogen evolution reaction, serving as a viable substitute for noble-metal-based systems in the pursuit of sustainable hydrogen production.

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The selective conversion of furfural is the key to the synthesis of bio-based fine chemicals, but it is still challenging due to the complexity of multi-pathway reactions. Herein, MOFs-derived 3D Cu@CN framework with layered structure were constructed via a dual-linkers strategy. The prepared Cu@CN-400 has good catalytic performance, the yield of furfuryl alcohol is more than 99%, and the catalyst can still maintain high activity after 10 cycles. The characterization and experimental results confirm that this strategy benefits the catalyst in two aspects, namely, the generation of a certain proportion of exposed Cu⁰ species and the formation of a layered structure with Cu embedded in nitrogen-doped carbon. The first aspect improves the activity of the catalyst, while the second aspect greatly inhibits the leaching of metal components during the reaction, thereby ensuring the stability of the catalyst. This study provides a feasible strategy for designing stable catalysts to achieve highly selective conversion of furfural.

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Pharmaceutical pollution, particularly contamination of aquatic environments, poses a significant global environmental challenge. This study introduces a novel photocatalytic approach for tetracycline removal using zinc-doped strontium magnesium aluminum ferrite (Zn_xSr_0.7−xMg_0.3Al_0.1Fe_1.9O₄, (x = 0, 0.3)) nanoparticles. We successfully engineered photocatalysts with enhanced structural and photocatalytic properties using a sophisticated sol–gel synthesis method. The zinc-doped material demonstrated remarkable improvements compared to its undoped counterpart. The key structural modifications included a reduced crystallite size (from 35.55 nm to 27.55 nm), significantly increased surface area (from 6.63 m²/g to 32.14 m²/g), and a narrowed bandgap (from 2.7 eV to 2.4 eV). These modifications directly translated into superior photocatalytic performance, with the tetracycline degradation efficiency increasing from 73.67 to 98.43%. Mechanistic investigations revealed the presence of hydroxyl radicals as the primary degradation mechanism, with first-order kinetics governing the reaction. The catalyst demonstrated exceptional stability, maintaining 93.45% degradation efficiency after five consecutive cycles. The quantum efficiency was improved by 34%, highlighting the potential of strategic metal doping for enhancing photocatalytic materials. This study provides a promising strategy for pharmaceutical pollution remediation and offers insights into advanced material design for environmental applications. Zinc-doped spinel ferrite represents a significant advancement in the development of efficient recyclable photocatalysts for water treatment.

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