Shape-controlled CuxCe1-xO2 nanorods catalyst and the active components functioned in selective oxidation of CO in hydrogen-rich stream

Abstract

A novel shape-controlled CuxCe1-xO2 nanorods catalyst is synthesized with a simple coprecipitation method at room temperature and Cu(I) chloride as copper sources for the first time. Various analysis methods (XRD Rietveld Refinement, N2 adsorption-desorption, dynamic OSC, XPS, HRTEM, H2-TPR and In situ DRIFTs) and catalytic activity test techniques are used to investigate the structural properties and the catalytic performance of the catalysts in CO-PROX. Introducing copper dopant into ceria nanorods has positive effect on enriching the lattice distortion, oxygen vacancy concentration and the lattice oxygen mobility of ceria support. The incorporation of copper ions generates two main types of active copper species that play different roles in CO-PROX. Specifically, the highly dispersed CuOx species determine the low-temperature CO oxidation activity, while strongly bound Cu-[Ox]-Ce species at the copper-ceria interface regulates the high-temperature CO oxidation activity of the catalyst. Appropriate copper doping (7–11 wt %) is in favor of forming sufficient CuOx species highly dispersed on the surface of ceria nanorods and accelerating the oxygen mobility, as well as strengthening the copper-ceria interaction in the catalyst, which significantly improves its catalytic activity and broadens the temperature window in CO-PROX.