PERFORMANCE OF DOPED PT TIO2 (W6+) CATALYSTS FOR COMBUSTION OF VOLATILE ORGANIC-COMPOUNDS (VOCS)/

The oxidation of benzene and ethylacetate, present in trace amounts in air, over Pt supported on gamma-Al2O3, SiO2, TiO2 and TiO2 (W6+) carr iers has been studied. It was found that doping of the TiO2 support wi th W6+ cations has a positive effect on the activity of Pt catalysts f or benzene and ethylacetate oxidation. A maximum in activity enhanceme nt has been observed at a W6+ content of 0.45 at% in the TiO2 support. The Pt/TiO2 (0.45 at% W6+) catalyst is over two orders of magnitude m ore active than the Pt/gamma-Al2O3 catalyst in the case of ethylacetat e oxidation and an order of magnitude more active in the case of benze ne oxidation. Doping of TiO2 with W6+ cations enhances its activity fo r ethylacetate degradation towards smaller organic intermediates, such as ethanol, acetic acid and ethylene, and it also affects product dis tribution. The enhanced activity of the Pt/TiO2 (W6+) catalysts is att ributed to complementary bifunctional steps occuring on sites offered by Pt metal and by the support. During oxidation of benzene-ethylaceta te-water mixtures, benzene oxidation is strongly suppressed in the pre sence of ethylacetate, while water acts as an inhibitor for both volat ile organic compounds (VOC) oxidations. (C) 1998 Elsevier Science B.V.