Enhanced photocatalytic activity of supported TiO2:: dispersing effect of SiO2

The physical and photocatalytic properties of the TiO2 loaded on a unique silica using a TiO2 sols, which was prepared by the hydrolysis of titanium R-butoxide in water (pH = 1.1) containing different alcohols and alcohol concentration, have been examined. Compared to the bare TiO2 prepared in parallel, all the supported TiO2 showed a higher photoactivity for the oxidation of acetophenone in water. The supported catalyst were mainly anatase crystallites of smaller size, and had a slightly higher adsorptivity toward the organic substrate. Upon the change of alcohols and alcohol concentration in the sol-gel mixture, the supported TiO2 exhibited different response from the bare TiO2 in the crystal structures and photoactivity. In addition, the supported TiO2 showed a higher photoactivity on a silica of smaller particle size than on the silica of larger particles. The results suggest that the dispersion effect of silica is operative, which could be the basic role of any porous support for the TiO2 photocatalysis. (C) 1999 Elsevier Science S.A. All rights reserved.