Sol-gel synthesis of vanadium doped titania: Effect of the synthetic routes and investigation of their photocatalytic properties in the presence of natural sunlight

Abstract

The development of visible-light effective TiO2 photocatalysts allows low cost degradation of toxic non-biodegradable organic pollutants. In the present study a series of vanadium doped titania (V-TiO2) photocatalysts with V-to-Ti of 0.03, 0.06 and 0.1 were synthesized by either one-step or two-step modified sol-gel approaches. Titanium oxychloride solution was used as a titania source while vanadium pentaoxide was used as a vanadia source to form V-TiO2 in the absence of surfactants. One-step process was performed through the reaction of the TiO2 source with vanadium source. In two-step route the Ti(OH)(4) gel was preformed through gelation of the TiO2 source using ammonium solution and then peptized in the acidic vanadium solution. The physicochemical properties of the samples were examined by XRF, XRD, UV-visible DRS, SEM-EDAX, TEM, DTA-TGA, XPS and nitrogen gas physisorption studies analyses. It was observed that the morphology, crystal structure and photochemical properties of the obtained samples were largely dependent on the calcination temperature, synthetic approach and V-to-Ti ratios. Calcination of the samples yielded large ultrafine and perhaps monodispersed particles with different sizes depending on the synthetic technique. The photocatalytic performance of the samples was tested in the photodegradation of methylene blue in the presence of natural sunlight. The photocatalytic activities of the samples synthesized by two-step route were higher than that of the samples yielded through one-step approach. Thus, the present report suggest systematic, convenient and cost-effective sol-gel techniques to yield V-TiO2 photocatalysts with harnessed photocatalytic performance for decolorization of toxic organic pollutants in the presence of natural solar irradiation. (C) 2015 Elsevier B.V. All rights reserved.