Photocatalytic oxidation of ethylene to CO2 and H2O on ultrafine powdered TiO2 photocatalysts: Effect of the presence of O-2 and H2O and the additionof Pt

The complete photocatalytic oxidation of C2H4 with O-2 into CO2 and H2O has been achieved on ultrafine powdered TiO2 photocatalysts and the addition o f H2O was found to enhance the reaction. The photocatalytic reaction has be en studied by IR, ESR, and analysis of the reaction products. UV irradiatio n of the photocatalysts at 275 K led to the photocatalytic oxidation of C2H 4 with O-2 into CO2, CO, and H2O. The large surface area of the photocataly st is one of the most important factors in achieving a high efficiency in t he photocatalytic oxidation of C2H4. The photo-formed OH species as well as O-2(-) and O-3(-) anion radicals play a significant role as a key active s pecies in the complete photocatalytic oxidation of C2H4 with O-2 into CO2 a nd H2O. Interestingly, small amount of Pt addition to the TiO2 photocatalys t increased the amount of selective formation of CO2 which was the oxidatio n product of C2H4 and O-2.