Surface Acidity and Photocatalytic Activity of TiO2, WO3/TiO2, and MoO3/TiO2 Photocatalysts

TiO[sub 2] powder samples were calcined at various temperatures and their photocatalytic activity toward the degradation of 1,4-dichlorobenzene was measured. The surface acidity of the sample was also determined by the n-butylamine titration method. A linear relationship between photocatalytic activity and surface acidity was observed for the TiO[sub 2] samples. WO[sub 3]/TiO[sub 2] mixed oxide powders and MoO[sub 3]/TiO[sub 2] greatly enhanced its photocatalytic properties. The addition of WO[sub 3] or MoO[sub 3] to TiO[sub 2] 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. 55 refs., 4 figs., 3 tabs.