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Preparation of Ag-AgVO3/g-C3N4 composite photo-catalyst and degradation characteristics of antibiotics
摘要： The degradation of tetracycline by silver vanadate (AgVO3), graphite-like carbon nitride (g-C3N4) and their composites was studied by visible light photocatalysis. Their structures and morphologies were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Their degradation intermediates were analyzed by GC-MS. Nanorod silver vanadate was synthesized by hydrothermal method. The results show that the gap between nanorods is reduced by adding spinning carbon nitride, and the photocatalytic performance of the composite is stronger than that of single material. The reaction rate constants of Ag-AgVO3/g-C3N4 composites were 0.0298 min-1, 2.4 and 2.0 times that of g-C3N4 (K=0.0125 min-1) and AgVO3 (K=0.0152 min-1), respectively. At 120 minutes, the degradation rate of the composites reached 83.6%. The degradation of tetracycline was confirmed by GC-MS, and a possible degradation process was proposed.
关键词： Photo-catalysis,Carbon nitride,Antibiotics,Visible light,Silver vanadate
更新于2025-11-21 10:59:37
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Evaluation of 3D gold nanodendrite layers obtained by templated galvanic displacement reactions for SERS sensing and heterogeneous catalysis
摘要： Dense layers of overlapping three-dimensional (3D) gold nanodendrites characterized by high specific surfaces as well as by abundance of sharp edges and vertices creating high densities of SERS hotspots are promising substrates for SERS-based sensing and catalysis. We have evaluated to what extent structural features of 3D gold nanodendrite layers can be optimized by the initiation of 3D gold nanodendrite growth at gold particles rationally positioned on silicon wafers. For this purpose, galvanic displacement reactions yielding 3D gold nanodendrites were guided by hexagonal arrays of parent gold particles with a lattice constant of 1.5 μm obtained by solid-state dewetting of gold on topographically patterned silicon wafers. Initiation of the growth of dendritic features at the edges of the gold particles resulted in the formation of 3D gold nanodendrites while limitation of dendritic growth to the substrate plane was prevented. The regular arrangement of the parent gold particles supported the formation of dense layers of overlapping 3D gold nanodendrites that were sufficiently homogeneous within the resolution limits of Raman microscopy. Consequently, SERS mapping experiments revealed a reasonable degree of uniformity. The proposed preparation algorithm comprises only bottom-up process steps that can be carried out without the use of costly instrumentation.
关键词： heterogeneous catalysis,galvanic displacement reactions,3D gold nanodendrites,SERS sensing,solid-state dewetting
更新于2025-11-19 16:56:35
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Cu3MS4 (M=V, Nb, and Ta) and their solid solutions with sulvanite structure for photocatalytic and photoelectrochemical H2 evolution under visible light irradiation
摘要： Solid solutions with a sulvanite structure between Cu3VS4 and either Cu3NbS4 or Cu3TaS4 (Cu3Nb1-xVxS4, Cu3Ta1-xVxS4) were successfully prepared by a solid-state reaction. Their band gaps were 1.6–1.7 eV corresponding to the absorption of a wide range of visible light. Ru-cocatalyst loaded Cu3MS4 (M=V, Nb, Ta), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 showed photocatalytic activities for sacrificial H2 evolution under visible light irradiation. Most solid solutions showed better activities than the single Cu3MS4 (M=V, Nb, Ta). Cu3MS4 (M=V, Nb), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 also functioned as a photoelectrode and gave cathodic photocurrents under visible light irradiation, indicating a p-type semiconductor character. Cu3Nb0.9V0.1S4 showed the best photocatalytic and photoelectrochemical performances. When Ru-loaded Cu3Nb0.9V0.1S4 was used as a photocathode with a CoOx-loaded BiVO4 photoanode, photoelectrochemical water splitting proceeded under simulated sunlight irradiation without an external bias.
关键词： Energy conversion,Water splitting,Heterogeneous catalysis,Photocatalysis
更新于2025-11-19 16:51:07
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Photocatalytic and Photo-Fenton Catalytic Degradation Activities of Z-Scheme Ag2S/BiFeO3 Heterojunction Composites under Visible-Light Irradiation
摘要： Z-scheme Ag2S/BiFeO3 heterojunction composites were successfully prepared through a precipitation method. The morphology and microstructure characterization demonstrate that Ag2S nanoparticles (30–50 nm) are well-decorated on the surfaces of polyhedral BiFeO3 particles (500–800 nm) to form Ag2S/BiFeO3 heterojunctions. The photocatalytic and photo-Fenton catalytic activities of the as-derived Ag2S/BiFeO3 heterojunction composites were evaluated by the degradation of methyl orange (MO) under visible-light irradiation. The photocatalytic result indicates that the Ag2S/BiFeO3 composites exhibit much improved photocatalytic activities when compared with bare Ag2S and BiFeO3. The optimum composite sample was observed to be 15% Ag2S/BiFeO3 with an Ag2S mass fraction of 15%. Furthermore, the addition of H2O2 can further enhance the dye degradation efficiency, which is due to the synergistic effects of photo- and Fenton catalysis. The results of photoelectrochemical and photoluminescence measurements suggest a greater separation of the photoexcited electron/hole pairs in the Ag2S/BiFeO3 composites. According to the active species trapping experiments, the photocatalytic and photo-Fenton catalytic mechanisms of the Ag2S/BiFeO3 composites were proposed and discussed.
关键词： polyhedral BiFeO3 particles,photo-Fenton catalysis,Ag2S nanoparticles,photocatalysis,Z-scheme Ag2S/BiFeO3 heterojunction
更新于2025-11-19 16:46:39
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Insights into the thermo-photo catalytic production of hydrogen from water on a low-cost NiOx-loaded TiO2 catalyst
摘要： Thermo-photo catalytic water splitting, where the introduction of thermal energy increases the oxidation driving force for narrow-band-gap photocatalysts (with a low valence band potential), exhibited significantly advanced performance for hydrogen production compared with general water splitting at room temperature. Herein, a low-cost NiOx-loaded TiO2 catalyst was reported for thermo-photo catalytic water splitting with methanol as the sacrificial agent. The catalyst with an optimal Ni ratio of 5 wt.% achieved a hydrogen evolution rate of 53.7 mmol/h/g under simulated AM 1.5G sunlight at 260℃, which was 2.5 times more than that without illumination, with apparent quantum efficiencies of 66.24%, 33.55%, 32.52% and 15.35% at 380, 420, 450 and 500 nm, respectively. More impressively, under the irradiation of visible light (λ>420 nm) at this temperature, and photohydrogen yield could still reach 26.9 mmol/h/g, which was 5 orders of magnitude greater than that (0.0011 mmol/h/g) conducted at room temperature. Isotope tracer experiments demonstrated that the introduction of photo energy promoted the hydrogen production mainly by enhancing hydrogen evolution from water splitting rather than methanol decomposition or reformation. Furthermore, the step-wise reaction mechanism was revealed with insights into the synergistic roles of thermo-energy and photo-energy for production of hydrogen from water. Those findings highlight the great promise of thermo-photo catalysis and should inspire more efforts for water splitting.
关键词： visible light,Hydrogen production,nickel-based catalysts,thermo-photo catalysis,titanium dioxide
更新于2025-11-14 17:03:37
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Preparation of α‐Si <sub/>3</sub> N <sub/>4</sub> by direct nitridation using the polysilicon waste by diamond wire cutting
摘要： With the rapid development of the semiconductor industry and solar photovoltaic industry, a large number of polysilicon wastes from diamond wire cutting are accumulated, which not only pollute the environment, but also cause safety problems due to the ultrafine particle size and high reactivity. The diamond wire cutting polysilicon waste was used to prepare α-Si3N4 by direct nitridation method. This method could not only fully recycle the waste and reduce environmental pollution, but also reduce the production cost of α-Si3N4. Furthermore, the effects of FeCl3, NaCl and metal Cu on the nitridation of polysilicon waste are investigated in detail, respectively. It is found that FeCl3 and NaCl are not ideal additives for the preparation of α-Si3N4. However, α-Si3N4 dominated Si3N4 can be obtained via adding 5 wt. % Cu after nitridation at 1250 oC for 8 h, and the relative content of α-Si3N4 reaches 92.37 %.
关键词： silicon nitride,crystal growth,nitridation,catalysts/catalysis,powders
更新于2025-11-14 14:48:53
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Spectroscopic and theoretical studies of potassium sodium l-(+)-tartrate tetrahydrate and l-tartaric acid used as precursors for in situ laser-induced deposition of the catalytically active copper microstructures
摘要： In this work we study the influence of l-(+)-КNaC4H4O6 × 4H2O (KNaT) and l-H2C4H4O6 (H2T) on the complexation processes occurring during in situ laser-induced catalytic destruction of the organic components of the aqueous solutions with formation of the unsaturated hydrocarbons. For that purpose, ATR-FTIR, Raman, IR, and NIR spectroscopy as well as quantum chemical calculations were implemented. It was observed that hydration of T2? anion via carboxylate groups is stronger than that via hydroxyl groups. We also established the changes in the spectral characteristics of the absorption bands corresponding to vibrations of T2?, HT?, and H2T, at solid state-liquid and acid-salt transitions, depending on concentration of the solution components and the [OH?]/[H2T] ratio. Finally, it was shown that ethylene is a main product of the catalytic destruction of the copper tartrate complexes.
关键词： IR,Laser-induced copper deposition,DFT calculations,Tartaric acid,ATR-FTIR,Catalysis,NIR,Raman spectroscopy,Sodium potassium tartrate tetrahydrate
更新于2025-10-22 19:40:53
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Merging Photoredox PCET with Ni-Catalyzed Cross-Coupling: Cascade Amidoarylation of Unactivated Olefins
摘要： A rapid, highly diastereoselective amidoarylation of unactivated olefins was achieved to render medicinally privileged pyrrolidinone structures. Taking advantage of a photoredox proton-coupled electron transfer process, amidyl radicals were obtained from non-prefunctionalized N–H bonds under mild conditions, which were subsequently trapped by pendant olefins, delivering alkyl radicals for nickel-catalyzed cross-coupling. Mechanistic studies revealed the key balance between thermodynamically-driven radical generation and kinetically-driven cyclization, which led to expanding the scope toward urea and carbamate substrates.
关键词： urea,nickel catalysis,carbamate,unactivated olefins,proton-coupled electron transfer,amidoarylation,photoredox catalysis,pyrrolidinone
更新于2025-09-23 15:23:52
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Effect of H?SO? Solution Treating on the Adhesion, Charge Transfer and Catalytic Performance of Screen‐Printed PEDOT:PSS
摘要： Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films screen-printed on fluorine-doped tin oxide (FTO) substrates, to improve their charge transfer efficiency. Different H2SO4 solutions including concentrated H2SO4 and H2SO4 diluted with H2O or dimethyl sulfoxide (DMSO) were adopted during the post-treatment. The adhesion of the as-treated films was evaluated by adhesive tape peeling tests, the surface morphology and vertical charge transfer from the films to the substrates were investigated by current-sensing atomic force microscopy, and the catalytic activities toward I3- reduction of PEDOT:PSS films were characterized via electrochemical measurements. It is discovered that selecting proper H2SO4 solutions is crucial to improve the charge transfer efficiency and catalytic performance while maintaining the reliable adhesion of the film on the substrates, and H2SO4/DMSO performs best as the solution for post-treatment. A schematic mechanism was proposed based on different interactions among solution, PEDOT:PSS and the substrate in the case of various post-treatment solutions.
关键词： charge transfer,poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate),screen printing,catalysis,post-treatment
更新于2025-09-23 15:23:52
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Enhanced Selectivity for Oriented Catalyzing Tetracycline by the Functional Inorganic Imprinted ZnFe <sub/>2</sub> O <sub/>4</sub> @Ag <sub/>3</sub> PO <sub/>4</sub> /SiO <sub/>2</sub> Photocatalyst with Excellent Stability
摘要： A novel functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst was synthesized by a facile sol-gel method combined with the surface imprinting technique, which possessed excellent stability. By optimizing the amount of materials to determine the preferable addition amounts of tetraethoxysilane (TEOS) and tetracycline are 0.06 mL and 0.06 g, respectively. This as-prepared functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst was proved to not only exhibit high photocatalytic activity (the photodegradation rate was 61.52% under the simulated sunlight irradiation of 60 min), but also possess a strong oriented ability to selectively recognize and photocatalyze tetracycline (the coe?cient of selectivity (kselectivity) was 5.14 for ciprofloxacin and 3.63 for gatifloxacin). Moreover, the functional inorganic imprinted ZnFe2O4@Ag3PO4/SiO2 photocatalyst prepared with SiO2 as the inorganic imprinted layer have good stability and can be recycled many times. This work not only puts forward a novel design idea of functional semiconductor materials but also is expected to be widely applied to the oriented catalysis for a target substance according to the practical requirement.
关键词： selectivity,stability,ZnFe2O4@Ag3PO4/SiO2,Inorganic imprinted photocatalyst,tetracycline oriented catalysis
更新于2025-09-23 15:23:52