Catalysis Letters最新文献

TiO₂ nanomaterials are widely valued for their stability, non-toxicity, and strong photocatalytic potential in environmental applications. This study investigates the effect of codoping on the structural and photocatalytic properties of TiO₂ nanoparticles by using singly doped samples as a reference for comparison. The nanoparticles were synthesized via the sol–gel method and characterized using X-ray diffraction (XRD), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy to evaluate their structural and optical behavior. Photocatalytic activity was assessed through the degradation of methylene blue (MB) in aqueous media, revealing that incorporating dopants notably improved pollutant degradation efficiency. UV–visible spectroscopy confirmed a red shift in the absorption edge, particularly pronounced in Zn and Zn/N codoped samples, indicating enhanced responsiveness to visible light. Zn and N codoping not only modifies the electronic structure of TiO₂ but also improves the density of active surface sites, thereby promoting the adsorption and subsequent transformation of reactants under visible light irradiation. Among the samples, the Zn/N codoped TiO₂ with the highest nitrogen content exhibited superior photocatalytic performance, achieving a 99% degradation rate of MB under visible light. These results highlight the critical role of synergistic dopant interactions in modifying both the bulk electronic structure and surface chemistry of TiO₂, resulting in enhanced charge carrier separation and improved photocatalytic efficiency. This work presents a viable strategy for visible-light-driven pollutant degradation, highlighting the potential of codoping approaches for designing high-performance TiO₂-based photocatalysts. Further investigation into dopant combinations and their mechanisms may open new pathways for optimizing TiO₂ photocatalysis in environmental remediation applications.

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Photocatalytic regeneration of nicotinamide adenine dinucleotide (NADH) is indispensable for the sustainability of enzyme-driven industrial processes. In this study, we developed a Z-scheme heterogeneous photocatalyst consisting of CdS and g-C₃N₄, which markedly enhanced visible-light absorption and photogenerated charge separation efficiency, and applied it to an in situ visible-light-driven NADH regeneration system. The synthesized catalyst afforded an exceptional NADH regeneration yield of 97.88% within just 15 min. Additionally, enzyme activity assays utilizing alcohol dehydrogenase (ADH) demonstrated that 67.60% of NAD⁺ was successfully converted into the enzymatically fraction, 1,4-NADH. Furthermore, formate dehydrogenase (FDH) immobilized on ZIF-8 was integrated into this NADH regeneration system, enabling highly sustainable biosynthesis of formic acid. During a 2 h continuous reaction, the integrated system successfully accumulated a total formic acid concentration of 0.88 mM. This novel Z-scheme photocatalytic system thus presented a highly effective solution for regenerating active NADH, providing valuable insights and promoting the development of photocatalysis-driven enzymatic systems for sustainable solar-to-chemical energy conversion.

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Lignin, a promising sustainable biopolymer, exhibits immense potential as a renewable feedstock for aromatic chemicals and advanced materials, offering a green alternative to fossil resources. However, its complex aromatic structure and recalcitrant β-O-4 ether bond pose significant challenges for efficient depolymerization. In this study, a series of Ce-modified Cu-Ni-Al layered double hydroxide (LDH) catalysts (CuNiAlCe_x) were designed for the catalytic transfer hydrogenolysis (CTH) of enzymatic hydrolysis lignin (EHL) using ethanol as a hydrogen donor, aiming to produce low-molecular-weight lignin oil (LO) enriched with phenolic hydroxyl groups. Structural and surface analyses revealed that Ce modification enhanced oxygen vacancy concentration through dynamic Ce³⁺/Ce⁴⁺ redox cycling and optimized acid site distribution, synergistically facilitating C-O bond cleavage. The highest LO yield of 71.8% was attained under optimized reaction parameters, accompanied by a marked reduction in molecular weight and concurrent increases in phenolic hydroxyl and carboxyl groups. GC-MS analysis identified diverse aromatic monomers (total yield: 21.34%), predominantly guaiacyl derivatives. This study reveals the synergistic interaction between oxygen vacancies and acid sites in CuNiAlCe_x catalysts, providing a green strategy for the selective valorization of lignin into aromatic compounds, thereby advancing sustainable biorefinery technology.

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Sulfur dioxide (SO₂) emissions, a major source of air pollution, can be effectively mitigated through catalytic reduction to elemental sulfur using carbon monoxide (CO). In this study, Fe loaded TiO₂ catalysts were synthesized and subsequently subjected to pre-sulfurization treatment under varied conditions. Their catalytic performance was evaluated in SO₂ reduction for thermal and dielectric barrier discharge (DBD) plasma enhanced thermal catalysis. The results showed that OFS-Fe/TiO₂ catalyst with oxygen-free sulfurization (OFS) treatment exhibited the highest catalytic activity, achieving above 90% SO₂ conversion between 250 and 550 °C under oxygen-assisted reaction (OAR), along with long-term stability under 40–60% water vapor. However, the SO₂ conversion were below 20% for Fe/TiO₂ and oxygen-assisted sulfurization OAS-Fe/TiO₂ catalysts within 250 to 400 °C. Notably, the significantly enhanced catalytic performance of the OFS-Fe/TiO₂ catalyst was probably attributed to the high dispersion of Fe over nano-TiO₂, the lower Fe²⁺/Fe³⁺ ratio, and the formation of active FeS₂ species detected by SEM-EDS, XPS and TPD techniques. Furethermore, a conversion efficiency exceeding 90% was maintained throughout 80 to 550 °C under DBD plasma reaction over POFS-Fe/TiO₂ catalyst with room-temperature DBD plasma oxygen-free sulfurization treatment, surpassing thermal catalysis performance. The significantly enhanced low-temperature activity of plasma catalysis was attributed to the lowest Fe²⁺/Fe³⁺ ratio, together with the transformation of FeS₂ into FeS, generating more sulfur vacancies. In-situ DRIFTS experiments confirmed two distinct SO₂ adsorption and reduction mechanisms between Fe/TiO₂ and OFS-Fe/TiO₂ catalysts. The results demonstrate that pre-sulfurization and plasma modification serve as an effective catalytic strategy to enhance CO-mediated SO₂ reduction, offering a sustainable emission control approach through sulfur resource utilization.

Graphical Abstract

The world is currently facing the dual challenges of energy scarcity and environmental degradation. As a highly promising carrier of clean and renewable energy, hydrogen has attracted significant attention, with high-efficiency water electrolysis recognized as a key pathway for the large-scale production of green hydrogen. Among various electrocatalysts, transition metal Co-V-based materials demonstrate remarkable potential. In this study, we successfully synthesized a highly stable amorphous Co-V-B catalyst on a nickel foam (NF) substrate by constructing a Co-V bimetallic system followed by boron doping to enhance its performance. Electrochemical evaluations indicated that the catalyst delivers superior Hydrogen evolution reaction (HER) performance, requiring only 47 mV overpotential to attain a current density of − 10 mA cm⁻², along with a low charge transfer resistance of 1.14 Ω. Additionally, the catalyst demonstrated remarkable durability, sustaining stable HER activity during 16 h of continuous chronopotentiometric (CP) operation. This study systematically explores the preparation of Co-V/NF catalysts and highlights the significant impact of boron incorporation on improving catalytic performance, providing meaningful guidance for developing advanced electrocatalysts for water splitting applications.

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Structured Pt-TM alloys (TM = 3d-transition metals) are considered potential electrocatalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), showing enhanced catalytic activities and durability with low Pt loading. These shaped Pt-TM alloys include three-dimensional (3D) polyhedra such as octahedrons, 3D hollow structures like nanoframes (NFs), or one-dimensional nanostructures such as nanowires or nanotubes. Pt-TM alloy NFs are particularly attractive because most of the Pt on the frameworks and ridges contributes to the catalytic activity, in contrast to solid nanocrystals with buried Pt sites. In this study, Pt-Ni alloy NFs were synthesized using a hot-injection co-reduction method, starting with solid-shaped Pt-Ni rhombic dodecahedrons (RDs) and followed by etching the sacrificial Ni in acetic acid to produce Pt-Ni nanoframes. Transmission electron microscopy (TEM) confirmed the successful synthesis of large Pt-Ni RDs, which were then effectively transformed into Pt-Ni NFs featuring a uniform distribution of Pt and Ni. Electrochemical analysis revealed an electrochemically active surface area of approximately 43.2 m²/g_Pt for the Pt-Ni NFs catalyst, with mass and specific activities measured at 0.359 A/mg_Pt and 0.829 mA/cm², respectively, both of which exceed the activities of the Pt-Ni RDs and commercial reference Pt/C catalysts.

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Titanium dioxide (TiO₂) is widely regarded as one of the most promising semiconductor materials for photocatalysis. In this study, through defect engineering, the strong interaction between F⁻ ions and surface Ti⁴⁺ is utilized to induce the generation of oxygen defects, thereby achieving selective etching and exposure of the high-energy {101} crystal plane. At the same time, the coordination effect of Ni on the surface metal active site not only promotes the transition of the forbidden band energy level, but also effectively narrows the band gap of TiO₂. Through systematic characterization, the successful coordination of Ni and the enhancement of the high-energy state crystal plane stability were confirmed. BET specific surface area test shows that the large specific surface area of Ni-TiO₂ samples provides more surface active sites for photocatalytic reactions. Photoelectric performance tests further show that the introduction of double defect engineering significantly improves the separation and migration efficiency of TiO₂ photogenerated carriers. Degradation experiments showed that Ni-coordinated TiO₂ could efficiently degrade phenol pollutants within 60 min, exhibiting excellent photocatalytic activity. Capture experiments further confirmed that the coupling between non-radical ¹O₂ and free radical •OH is the main active species in photocatalytic degradation. The synergistic effect of the generation of high-energy state facets and Ni coordination significantly improves the separation and migration of photogenerated carriers, thereby enhancing the photocatalytic performance. This work provides a reliable defect engineering strategy for improving the photocatalytic performance of TiO₂.

Graphical Abstract

In this study, through defect engineering, the strong interaction between F⁻ ions and surface Ti⁴⁺ is used to induce the generation of oxygen defects, thereby achieving selective etching and exposure of high-energy {101} crystal planes. At the same time, the coordination effect of Ni on the surface metal active sites not only promotes the transition of the forbidden band energy level, but also effectively narrows the band gap of TiO₂. By carefully designing the photocatalytic process, direct degradation of phenol was achieved under the coupling of non-radicals and free radicals. The improvement in photocatalytic activity is due to the increase in specific surface area, which not only broadens the light absorption capacity but also significantly improves the separation and migration of photogenerated carriers. The capture experiment further verified the efficient catalytic mechanism of the Ni-TiO₂/phenol system, demonstrating that the synergistic effect of the high-energy {101} cry