Origin of High Activity and Selectivity of CuO/CeO2 Catalysts Prepared by Solution Combustion Synthesis in CO-PROX Reaction

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 H2, 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 H2 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.