Three-dimensionally ordered macroporous Cr2O3−CeO2: High-performance catalysts for the oxidative removal of trichloroethylene

Abstract

Abstract Three-dimensionally ordered macroporous (3DOM) CeO2, 3DOM Cr2O3, 3DOM xCr2O3−CeO2 (x (the weight percentage of Cr2O3) = 3.5, 5.5, and 8.0 wt%), and 5.5 wt% Cr2O3/3DOM CeO2 samples were prepared using the polymethyl methacrylate (PMMA)-templating and incipient wetness impregnation methods, respectively. A number of techniques were used to characterize physicochemical properties of the materials, and their catalytic activities were evaluated for the oxidation of trichloroethylene (TCE). These samples possessed a good-quality 3DOM structure and a surface area of 35−47 m2/g. The 3DOM 5.5Cr2O3−CeO2 sample performed the best (the temperature at TCE conversion = 90% = 255 °C at a space velocity of 20,000 mL/(g h)). Effects of water vapor and carbon dioxide on activity of the 5.5Cr2O3−CeO2 sample were also examined. It is observed that partial deactivation induced by H2O introduction of the 5.5Cr2O3−CeO2 sample was reversible, while that induced by CO2 addition was irreversible. Based on the activity data and characterization results, it is concluded that the good catalytic activity and thermal stability of 3DOM 5.5Cr2O3−CeO2 was associated with its high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Cr2O3 and CeO2. We believe that the 3DOM 5.5Cr2O3−CeO2 catalyst is promising in the application for oxidative removal of chlorinated volatile organic compounds.