Catalytic Activity of MoO3 and V2O5 Highly Dispersed on TiO2 for Oxidation Reactions

The structure of Mo–Ti oxide catalysts has been investigated by using IR and XRD techniques. At a low Mo content, MoO3 is highly dispersed on TiO2, an amorphous phase being formed. Simultaneously, a shift of the Mo=O band from 995 cm−1 to 950 and 905 cm−1 takes place. The maximum rate of the oxidation of C2H5OH and C3H6 over Mo–Ti-6(atom% of Mo) is attributable to the weakening of the Mo=O bond. The 18O tracer and kinetic studies of the oxidation of C3H6 over Mo–Ti and V–Ti oxides suggest that a redox mechanism is applicable, the rate constants of reduction and reoxidation step being determined. The promoter action of TiO2 support is attributed mainly to the increase in the rate of reduction step.