The enhancement of redox reactions with mixed oxide catalysts by the sol–gel process

The enhancement of the photocatalytic activity of TiO 2 was investigated as a function of added amount of other oxides to promote desired oxidation or reduction reactions. Mixed oxides of Nb 2O 5 or Li 2O with TiO 2 were prepared by the sol–gel process. The target material of dichloroacetic acid (DCA) was chosen for oxidation reactions and K 2Cr 2O 7 for reduction. While the Nb 2O 5/TiO 2 had a deleterious effect on the decomposition rate of DCA, the excess electrons due to the doping of Nb 2O 5 into TiO 2 promoted the reduction process for Cr 6+. Li 2O (1 wt%) with TiO 2 was found the most efficient photocatalyst for DCA oxidation, resulting in photocatalytic activity of 50%.