Combustion of volatile organic compounds over composite catalyst of Pt/γ-Al2O3 and beta zeolite

Abstract

Catalytic oxidation of volatile organic compounds (VOCs) was carried out over a composite catalyst comprising Pt/γ-Al2O3 and protonated beta zeolite. The conversion of several VOCs such as ethyl acetate, butyl acetate, 2-propanol, 1,2-dichloroethane, and chloroethane over the composite catalyst was higher than the conversion over the conventional Pt/γ-Al2O3 catalyst, indicating a remarkable improvement in the oxidation activity of the composite. On the other hand, no difference in the conversion of methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and chloroethylene was observed for the composite catalyst versus the Pt/γ-Al2O3 catalyst. To clarify the role of the zeolite component, the reaction products obtained using the composite catalyst were compared with those obtained using the Pt/γ-Al2O3 catalyst. For the cases in which considerable improvement in the oxidation activity was observed with the composite, it was revealed that the conversion of VOCs to intermediate compounds took place over the acidic sites of the zeolite; the intermediates tended to be easily oxidized to CO2 on the Pt/γ-Al2O3 catalyst. In addition, the composite catalyst also exhibited high durability. High catalytic activity was maintained even after aging at 600°C for more than 1000 h.