LAUSR

Abstract The morphology effects on the activity and stability of Ce-Mn oxide catalysts for chlorobenzene (CB) and toluene oxidation were compared and investigated in this work. Ce-Mn nano-sheets (CM S), nano-particles (CM P) and nano-rods (CM R) were firstly prepared. The obvious morphology effects on the reactions were observed: the activity for toluene oxidation followed the order of CM S > CM P > CM R. In contrast, the activity for CB oxidation followed the order of CM R > CM P > CM S. For toluene oxidation, toluene adsorption and the C H bond dissociation occurred at lower temperatures on the CM S catalyst. The experimental results demonstrated that the higher content of surface adsorbed oxygen species and oxygen vacancies, as well as the enhanced Olatt species mobility of the CM S catalyst were responsible for its highest catalytic activity. For CB oxidation, inactive planar CB adsorption on the 2D surface of CM S catalyst and the strongly adsorbed Cl species from the CB decomposition resulted in serious deactivation of the catalyst. On the other hand, CB adsorption and the C-Cl bond dissociation occurred at lower temperatures on the CM R catalyst, Cl-contained species can be easily removed during the Deacon Reaction and gas phase oxygen can be adsorbed on the CM R surface to replenish the consumed oxygen, resulting in the improved activity and stability. These results showed that the catalytic performance of Ce-Mn oxides for CB and toluene oxidation was greatly affected by their morphologies.