A visible-light response vanadium-doped titania nanocatalyst by sol-gel method

A series of vanadium-doped TiO2 catalysts were synthesized by two modified sol-gel methods. V-doped TiO2 was found to be mainly preserved its anatase phase after calcination at 400degreesC. The TEM micrographs showed the sizes of primary particles were in the range of 6-20 nm. The increase of vanadium doping promoted the particle growth, and enhanced "red-shift" in the UV-Vis absorption spectra. The XPS (X-ray photoelectron spectroscopy) could not detect vanadium indicating negligible vanadium on the surface of catalysts, furthermore, there were also no peak of vanadium oxide in the XRD patterns. XAS (X-ray absorption spectroscopy) analysis indicating V4+ instead of V5+ implied that vanadium either substituted Ti4+ site or embedded in the vacancy of TiO2 structure. Therefore, vanadium was concluded to be highly dispersed inside the TiO2 structure. The photocatalytic activity was evaluated by the degradation of crystal violet (CV) and methylene blue (MB) under visible light irradiation. The degradation rate of CV and MB on V-doped TiO2 were higher than those of pure TiO2. As the results, V-doped TiO2 possessed better absorption ability of visible light. (C) 2004 Elsevier B.V. All rights reserved.