Catalytic and Photocatalytic Oxidation of Ethylene on Titania-Based Thin-Films

The effect of reaction temperature on the catalytic and photocatalytic oxidation of ethylene on unplatinized and platinized versions of a TiO 2 /ZrO 2 mixed-oxide thin-film catalyst is presented in this study. Ethylene conversion data collected using a recirculating tubular reactor are analyzed using a half order model of reaction kinetics. When operated in the presence of UV, both catalysts exhibit significant (95% confidence) increases in the reaction rate constant at 70 °C compared to 30 °C no difference is observed between unplatinized and platinized versions at these two temperatures. However, only the platinized catalyst performs better at 107 °C compared to its performance at 70 °C. Also, at 107 °C in the presence of UV, the reaction rate constant obtained for the platinized catalyst is a factor of 2 larger than that obtained using the unplatinized catalyst. Catalytic reaction rate constants for the platinized catalyst were 1 (107 °C) to 2 (70 °C) orders of magnitude lower than corresponding photocatalytic reaction rate constants. Comparisons between the thin-film catalysts studied here and a previously reported particulate catalyst show a fundamental difference in photocatalytic behavior, mainly due to insufficient utilization of the internal bulk of the particulate catalyst.