Synergistic effects of sulfation and co-doping on the visible light photocatalysis of TiO 2

Abstract

Sol–gel synthesis and sulfation process has been carried out to prepare Fe 3+/Zn 2+ co-doped and SO 4 2− impregnated TiO 2 photocatalysts. The aim of the present investigation is to improve the visible light photocatalytic activity of TiO 2 using (i) co-doping with transition metal species, Fe 3+/Zn 2+ and (ii) sulfur impregnation procedures. Structural (XRD) characteristics of SO 4 2− impregnated TiO 2 reveals the presence of anatase nanoparticles with average grain sizes of 9.8 and 14.8 nm. This sulfation process inhibits, the anatase to rutile phase transformation of TiO 2 at higher calcination temperatures (e.g. 600 °C) and increases the number and strength of surface acid sites. The UV–vis photocatalytic activity between the sulfated and non-sulfated Fe 3+/Zn 2+ co-doped TiO 2 catalysts have been found roughly the same. However, there is an enhancement in the visible light photoactivity, which is clearly discernable from the degradation of phenol in aqueous medium.