Enhanced photocatalytic activity of supported TiO2: dispersing effect of SiO2

The physical and photocatalytic properties of the TiO2 loaded on a unique s ilica using a TiO2 sols, which was prepared by the hydrolysis of titanium R -butoxide in water (pH = 1.1) containing different alcohols and alcohol con centration, have been examined. Compared to the bare TiO2 prepared in paral lel, all the supported TiO2 showed a higher photoactivity for the oxidation of acetophenone in water. The supported catalyst were mainly anatase cryst allites 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 partic le size than on the silica of larger particles. The results suggest that th e dispersion effect of silica is operative, which could be the basic role o f any porous support for the TiO2 photocatalysis. (C) 1999 Elsevier Science S.A. All rights reserved.