For emission control of volatile organic compounds (VOC), e.g., in the painting and printing industries, conventional Pt/Al2O3 and Co3O4-CeO2 catalysts are used. On the Pt/Al2O3 catalyst, aromatic hydrocarbons containing a benzene ring such as toluene can be oxidized at a lower complete oxidation temperature than on Co3O4-CeO2, under typical treatment conditions. However, ethyl acetate and isopropyl alcohol can be oxidized at a lower complete oxidation temperature on Co3O4-CeO2 than on Pt/Al2O3. In this study, platinum was directly supported on Co3O4-CeO2. Using chloroplatinic acid, the platinum cohered and the catalytic activity did not improve. But when the platinum was supported using platinum colloid coated with dispersant, high-dispersion support of the platinum on the Co3O4-CeO2 surface was achieved, and toluene, ethyl acetate, and isopropyl alcohol could be oxidized at less than 250 degrees C.