Facile synthesis of multi-shelled hollow Cu-CeO2 microspheres with promoted catalytic performance for preferential oxidation of CO

Preferential oxidation of CO is beneficial to the removal of residual poisonous CO in reformate gas for proton exchange membrane fuel cell. Cu-CeO2 has been widely studied as a promising catalyst for this application. Herein, we have synthesized multi-shelled hollow Cu-CeO2 microspheres by a facile and one-step aerosol spray pyrolysis. Repeated and asynchronous combustion of carbon during the pyrolysis process results in the formation of multi-shelled hollow structure. Meanwhile, surface enrichment and high dispersion of copper species are achieved. This novel Cu-CeO2 catalyst exhibits full CO conversion in H-2-rich stream within a rather wide temperature window from 130 degrees C to 190 degrees C and a satisfying O-2 selectivity. In addition, it displays a decent catalytic stability, with a slight conversion decay of 3.3% and a high O-2 selectivity around 94% in continuous flow for 20 h. Based on the synergetic mechanism of copper-ceria catalysts, highly dispersed copper species and abundant CuOx/CeO2 interfaces in multi-shelled hollow microspheres give rise to the changes of redox properties and CO adsorption properties, and thus result in promoted catalytic performance.