SURFACE-ACIDITY AND PHOTOCATALYTIC ACTIVITY OF TIO2, WO3 TIO2, AND MOO3 TIO2 PHOTOCATALYSTS

TiO2 powder samples (Degussa P25) were calcined.at various temperatures and their photocatalytic activity toward the degradation of 1,4-dichlorobenzene was measured. The surface acidity of the samples was also determined by the n-butylamine titration method. A linear relationship between photocatalytic activity and surface acidity was observed for the TiO2 samples. WO3/TiO2 mixed oxide powders and MoO3/TiO2 mixed oxide powders were prepared by an impregnation technique. The addition of WO3 or MoO3 to TiO2 greatly enhanced its photocatalytic properties. The addition of WO3 or MoO3 to TiO2 also increased the catalysts' surface acidity, as determined by the n-butylamine titration method. A correlation between the maximum photocatalytic activity and the maximum surface acidity was observed. Whereas acidity may not be the only factor which influences activity, it is certainly an important one.