Catalytic oxidation of gaseous benzene with ozone was carried out over supported manganese oxides to investigate the factors controlling the catalytic activities. The rate for benzene oxidation linearly increased with the surface area of catalyst, regardless of the kinds of catalyst support, whereas the ratio of ozone decomposition rate to benzene oxidation rate was larger for SiO2-supported catalyst than Al2O3-, TiO2, and ZrO2-supported catalysts. The rate for benzene oxidation and CO. selectivity increased with the reaction temperature (22-100 degrees C) and were improved by the addition of water vapor to reaction gases. Benzene conversion and carbon balance increased with ozone concentration. (C) 2008 Elsevier B.V. All rights reserved.