GAS-PHASE OZONE DECOMPOSITION CATALYSTS

Catalytic ozone decomposition is of practical significance because ozo ne is a toxic substance commonly found or generated in human environme nts (aircraft cabins, offices with photocopiers, laser printers, steri lizers). Considerable work has been done on ozone decomposition, most of it reported in the patent literature. This review provides a compre hensive summary of this literature, concentrating on analysis of the c omposition, preparation procedure and performance of the catalysts. Th is is supplemented by experimental work on kinetics and catalyst chara cterization 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, e xplaining its prevalence in patent disclosures. The kinetics of the re action 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 su peroxo surface intermediate.