Gas phase ozone decomposition catalysts

Catalytic ozone decomposition is of practical significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition, most of it reported in the patent literature. This review provides a comprehensive summary of this literature, concentrating on analysis of the composition, preparation procedure and performance of the catalysts. This is supplemented by experimental work on kinetics and catalyst characterization which ties together the previously reported results. It is found that p-type oxide semiconductors are the most active substances for ozone decomposition. Among these MnO2 has the highest activity, explaining its prevalence in patent disclosures. The kinetics of the reaction on MnO2 is zero order in oxygen and water vapor and two-thirds order in ozone, and is consistent with the existence of a peroxo or superoxo surface intermediate.