Enhanced visible-light photocatalytic activity of V2O5/S-TiO2 nanocomposites

Diverse approaches are being made in search of a visible-light active TiO2 photocatalysts. In this study. S-TiO2(x) nanocatalysts with x=2, 4 and 6 (x=S/Ti molar ratio) were synthesized by sol-gel method and V2O5/S-TiO2(x) nanocomposites by wet impregnation method using ammonium metavanadate as a source of vanadium. The synthesized catalysts were characterized by diffuse reflectance UV-vis spectroscopy, X-ray diffraction, Raman spectroscopy, N-2 adsorption desorption studies, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and high resolution transmission electron microscopy techniques. The photogenerated reactive species center dot OH radical estimated from photoluminescence spectra was directly correlated to the visible-light absorption of the catalyst. The photocatalytic activities of all the synthesized catalysts were evaluated for the degradation of MB under visible light irradiation. The excellent stability of V2O5/S-TiO2(x) nanocomposites has been revealed from the linear relationship between the fluorescence intensity and the time. The addition of sulfur and V2O5 to TiO2 has significantly enhanced the visible-light photocatalytic activity by modifying the optical and electronic properties of TiO2. The enhanced visible-light photocatalytic activity has been attributed to the efficient visible-light absorption of V2O5/S-TiO2(x) nanocomposites and efficient charge separation due to migration of charge carriers between S-TiO2 and V2O5. (C) 2012 Elsevier B.V. All rights reserved.