Origin of high activity and selectivity of CuO/CeO2 catalysts prepared by solution combustion synthesis in CO-PROX reaction

Abstract

A CuO/CeO2 catalyst with 4 wt % CuO nominal content has been prepared by solution combustion synthesis (SCS) and characterized by ICP-MS, BET surface area analysis, XPS, HRTEM, and H-2, and/or CO TPR. The catalyst, showing a rather homogeneous distribution of copper that strongly interacts with ceria, has been tested in CO-PROX reaction. The enhanced performance of the catalyst compared to that of an impregnated sample with the same copper loading has been explained by modeling the experimental CO2 temperature-programmed desorption (TPD) curve, which allowed the determination and quantification of different active sites. The temperature range of activity and the ratio of the amount of sites activating CO and H-2 oxidation, respectively, estimated for the two catalysts through the model explain the superior performance of the sample prepared by SCS despite its lower surface area.