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, N2 adsorption desorption studies, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and high resolution transmission electron microscopy techniques. The photogenerated reactive species 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.

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► S-TiO2(x) has been synthesized by sol–gel method.
► V2O5/S-TiO2(x) has been synthesized by wet impregnation method.
► The addition of V2O5 to S-TiO2 has enhanced the visible-light absorption.
► The migration of charge carriers in V2O5/S-TiO2 increased the activity.
► The stability of the nanocomposites has been revealed from the fluorescence study.