Effect of Ni doping on the catalytic properties of nanostructured peony-like CeO2

Nanostructured ceria materials have attracted wide attention as catalysts, and the doping of these materials with rare earth elements to modify their catalytic activity has been comprehensively investigated. A novel type of Ni-doped hierarchical nanostructured peony-like ceria (PCO) has been prepared and its catalytic activity is investigated and compared with that of Ni-loaded samples. The prepared Ni-doped ceria have nanoscale grain sizes and open mesopores. This unique morphology endows it with superior catalytic activity for the oxidation of CO and the partial oxidation of methane. It is found that extra oxygen vacancies are generated in the ceria, and the reducibility of the ceria is highly enhanced after Ni-doping. The catalytic activity for CO oxidation is improved after Ni-doping, compared with that of pure ceria and Ni-loaded ceria. In the reaction for the partial oxidation of methane, the 3.8 atm% Ni-loaded PCO sample realizes a higher CH4 conversion than the Ni-doped ceria. However, it is found that the onset temperature for CH4 conversion decreases from 400 degrees C for the pure PCO and 3.8 atm% Ni-loaded PCO sample, to 340 degrees C for the 5.7 atm% Ni-doped PCO sample. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.