Abstract: Activated carbon-supported gold catalysts were prepared by the incipient wetness method and characterized by N2 adsorption andX-rayphotoelectron spectroscopy. The catalyst activity for the decomposition of low-level ozone was evaluated, and the effects of pretreatment of activated carbon and post-treatment methods were investigated. Pretreatment of the activated carbon with dilute nitric acid and NaBH4 reduction could improve activity for ozone decomposition. The catalytic activity tests were conducted with feed gas of 45 mg/m3 ozone in air and relative humidity 60% at room temperature. The contact time was controlled at 0.06 s. The ozone removal ratio was maintained at 100% in the beginning1000min when the support was pretreated with HNO3 and NaBH4 and the catalyst was reduced with H2. Then it slowly dropped off to 97% in the following5000min. After pretreatment of the support by NaBH4, the specific surface area, pore volume, and elemental C fraction increased, but oxygen-containing groups decreased. This might be responsible for the improvement of catalytic activity. After gold was supported on the activated carbon, the catalyst surface area and pore volume further increased. However, the graphitic carbon fraction decreased whileC-Oand COO-groups increased. After reaction with ozone, the surface area and pore volume of samples as well as graphitic C content decreased, while the amount of C-O, COO-, andC=Ogroups increased. This indicated that activated carbon was catalyzed by gold to react with ozone and thereby ozone was decomposed.

Key words: ozone decomposition, activated carbon, gold, supported catalyst