CO Oxidation over Nanostructured Ceria Supported Bimetallic Cu-Mn Oxides Catalysts: Effect of Cu/Mn Ratio and Calcination Temperature

Nanostructured CeO2 supported CuO-MnO2 (CuMn/Ce) catalysts were synthesized by wet co-impregnation method and compared with CuO/CeO2 and MnO2/CeO2 catalysts on CO oxidation. The former shows significantly higher catalytic activity toward CO oxidation than the bimetallic oxides catalysts with minimum T-50. Dual synergistic effects in the interfaces of CuO-MnO2 and CuO-CeO2 shall be responsible for the higher oxidation performance of CuMn/Ce catalyst. As Cu/Mn mass ratio varies from 1/0.2 to 1/9, CO oxidation activities of the catalysts present unimodal distribution, and the catalyst with Cu/Mn = 1/1 shows the highest performance (T-50 = 45.8 degrees C; Ea = 24.11 kJ mol(-1)). Cu acts as CO dissociative adsorption sites, and Mn-Ce supplies activated O species from gas molecule and lattice oxygen, which are both indispensable for improving utilization efficiency of the reactants in the dual redox processes. The catalytic performance of catalyst is also vitally correlated with calcination temperature (160-320 degrees C). The optimum calcination temperature of CuMn/Ce catalyst is 320 degrees C. Catalyst characterization results indicate that the pretreatment at 320 degrees C is decent to obtain desired metal oxides along with fine texture properties.