Improving The Co-Prox Performance Of Inverse Ceo2/Cuo Catalysts: Doping Of The Cuo Component With Zn

An inverse CeO2/CuO catalyst in which the CuO component has been doped with Zn is examined in comparison with the analogous Zn-free catalyst with the aim of enhancing the performance of this type of systems for preferential oxidation of CO in H2-rich stream (CO-PROX). The catalysts are characterized by XRD, Raman spectroscopy, XANES-EXAFS, XPS, and HRTEM. Their catalytic properties are explored in conjunction with redox properties studied by XANES, XRD, and DRIFTS under reaction conditions with MS detection. It is shown that the presence of zinc enhances the CO-PROX performance of the inverse system through decreasing its H2 oxidation activity, while the CO oxidation activity does not practically become affected. This is related to an increase in the CO2 selectivity of the catalyst that has been attributed to a hindering of the reduction of the CuO component, thus preventing the formation of H2 oxidation active sites under reaction conditions. A model of the structural and catalytic effects induced by the presence of zinc in the catalyst is proposed on the basis of the multitechnique approach employed.