Catalytic total oxidation of 1,2-dichloroethane over highly dispersed vanadia supported on CeO2 nanobelts

CeO2 nanobelts were synthesized via a facile aqueous-phase precipitation route under mild conditions (template-free and non-hydrothermal), and then the highly dispersed vanadia catalysts with a wide range of VOx loadings were prepared by a conventional incipient-wetness impregnation method. The target VOx/CeO2 catalysts were characterized in detail and used in catalytic combustion of 1,2-dichloroethane (DCE). The results revealed that the monolayer dispersed VOx (6.0%VOx/CeO2) exhibited the most outstanding initial and stable activities, however, the main product containing carbon was CO2 not desired CO2. A reaction mechanism of DCE total oxidation was proposed based on the study of TPSR and in situ FTIR. The first step of this mechanism was considered to be a dissociative adsorption of C-Cl bonds on Lewis acid sites (such as Ce4+/3+, V5+/4+ or Ce3+-O2--V5+) via Cl abstraction, and then the dissociated DCE can be oxidized directly to CO2 by surface active oxygen species over pure CeO2. Whereas, over VOx/CeO2 catalysts, the formation of intermediate acetaldehyde was a key step via C-H bond activation and hydrogen transfer on VOx species, subsequently, partially oxidized to CO by the lattice oxygen of VOx. (C) 2014 Elsevier B.V. All rights reserved,