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Citric acid-modulated in situ synthesis of 3D hierarchical Bi@BiOCl microsphere photocatalysts with enhanced photocatalytic performance
摘要: 3D hierarchical Bi@BiOCl microspheres were successfully synthesized by a facile solvothermal method using citric acid as a modulating agent and the growth process was revealed. The modulation of citric acid not only reduced the size of BiOCl nanosheets, finally transforming BiOCl microflowers into microspheres, but also induced the in situ reductive deposition of metallic Bi on the surface of the microspheres. Consequently, Bi@BiOCl microspheres showed larger specific surface areas and total pore volumes, higher absorptivity to the visible light and better charge transfer ability than BiOCl microflowers. As a result, Bi@BiOCl microspheres exhibited much better photocatalytic performance than BiOCl microflowers. Bi@BiOCl microspheres modulated by 2.8 g citric acid showed the highest photocatalytic activity, which was 4.4 and 2.5 times higher than BiOCl microflowers in degrading RhB under visible light and salicylic acid under UV light, respectively. This work may provide a new insight into simultaneous size control and in situ metal deposition for Bi-containing photocatalysts and other materials.
关键词: solvothermal method,Bi@BiOCl microspheres,photocatalytic performance,citric acid modulation,in situ reductive deposition
更新于2025-09-04 15:30:14
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Fabrication of large surface area nitrogen vacancy modified graphitic carbon nitride with improved visible-light photocatalytic performance
摘要: In this work, nitrogen vacancy modified graphitic carbon nitride (g-C3N4) with large surface area was synthesized and analyzed by a series of instruments, including XRD, FTIR, XPS, EPR SEM, TEM, DRS and PL, etc. and the photocatalytic H2-evolution activity was investigated. The results indicated that the as-synthesized g-C3N4 with nitrogen vacancy exhibited stronger visible light response capability, enlarged specific surface area and notably separated rate of photoinduced charge carriers, which caused the as-synthesized photocatalyst possessing the higher hydrogen evolution rate (5250 μmol h?1 g?1) and excellent recycle stability. Evidently, this work could provide a new insight for preparing highly efficient photocatalyst.
关键词: Large surface area,Nitrogen vacancy,Photocatalysis,g-C3N4,Photocatalytic performance
更新于2025-09-04 15:30:14
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A Facile Green Approach for Synthesis of Selenium Nanowires with Visible Light Photocatalytic Properties
摘要: In this work, high purity trigonal selenium (t-Se) nanowires were synthesized through a simple one-step solvothermal process at 50 °C. Sodium formaldehyde sulfoxylate (SFS) was used as a reducing agent. To our knowledge, this is the first time that SFS was used as the reducing agent for synthesis of Se nanostructures. In this method, Se nanowires were obtained at lower temperature, shorter period of reaction time and without using complex equipment. The experimental parameters, such as reaction duration, temperature and amount of surfactant, were investigated. The as-prepared Se nanowires have a diameter of about 100–200 nm and length of up to 10 μm. A “Solid–Solution–Solid” growth mechanism was proposed. In the presence of H2O2, the Se nanowires showed good catalytic performance, where over 99% of methylene blue (MB) was degraded in 3.0 h. Results from this study demonstrated that the Se nanowires exhibit a promising application for photodegradation.
关键词: Synthesis,Photocatalytic Performance,Selenium,Nanowires
更新于2025-09-04 15:30:14
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Enhanced Visible Light Sensitization of N-doped TiO2 Nanotubes Containing Ti-Oxynitride Species Fabricated via Electrochemical Anodization of Titanium Nitride
摘要: The concentration and chemical state of nitrogen represent critical factors to control the band-gap narrowing and the enhancement of visible light harvesting in nitrogen-doped titanium dioxide. In this study, photocatalytic TiO2-N nanoporous structures were fabricated by the electrochemical anodization of titanium nitride sputtered films. Doping was straightforwardly obtained by oxidizing as-sputtered titanium nitride films containing N-metal bonds varying from 7.3 to 18.5 % in the Ti matrix. Severe morphological variations into the as-anodized substrates were registered at different nitrogen concentration and studied by Small-Angle X-ray Scattering. Titanium nitride films with minimum N content of 6.2 at% N led to a quasi-nanotubular geometry, whilst an increase in N concentration up to 23.8 at% determined an inhomogeneous, polydispersed distribution of nanotube apertures. The chemical state of nitrogen in the TiO2 matrix was investigated by X-ray Photoelectron Spectroscopy depth profile analysis and correlated to the photocatalytic performance. The presence of Ti-N and β-Ti substitutional bonds, as well as Ti-oxynitride species was revealed by the analysis of N 1s X-ray Photoelectron Spectroscopy High Resolution spectra. The minimum N content of 4.1 at% in the TiO2-N corresponded to the lowest Ti-oxynitride ratio of 13.5 %. The relative variation of N-metal bonds was correlated to the visible light sensitization and the highest Ti-N/Ti oxynitride ratio of 3.3 was attributed to the lowest band-gap of 2.7 eV and associated to a threefold increase in the degradation of organic dye. Further increase of N doping led to a dramatic drop of Ti-N/Ti oxynitride ratio, from 3.3 to 0.4, which resulted in a loss photocatalytic activity. The impact of the chemical state of nitrogen towards efficient doping of TiO2 nanotubes is demonstrated with a direct correlation to the N loading and a strategy to optimise these factors based on a simple, rapid synthesis from titanium nitride.
关键词: visible light sensitization,photocatalytic performance,titanium nitride,nitrogen-doped titanium dioxide,electrochemical anodization
更新于2025-09-04 15:30:14