The effect of copper species in copper-ceria catalysts: structure evolution and enhanced performance in CO oxidation

摘要

In this paper, copper doped ceria porous nanospheres were synthesized using carbon nanospheres as a hard template via a homogenous precipitation method at low temperature. The results showed that the copper-doped ceria has undergone a morphology transformation from the initial double-shell spheres to hollow spheres as the copper doping concentration increased from 0 to 7.5%(mol). Notably, the Cu/Ce + Cu atomic ratio in the final products was approximately five times the initial design ratio, which confirmed an efficient utilization of copper in this system. Furthermore, the copper-ceria catalysts exhibited enhanced catalytic performance towards CO conversion when compared with pure ceria catalysts (e.g., for the optimal catalysts, the complete conversion temperature was 160 degrees C, for the pure catalysts, complete conversion temperature was 300 degrees C). Through the analysis of the catalysts structure, we proved that the superior catalytic performance was derived from a combination of CuOx clusters and copper ions in the Cu-[O-x]-Ce bulk phase.