Operando DRIFTS and XANES Study of Deactivating Effect of CO2on a Ce0.8Cu0.2O2CO-PROX Catalyst

Abstract

Deactivating effects produced by CO2 on a catalyst combining oxidized copper and cerium prepared by microemulsion−coprecipitation and employed for preferential oxidation of CO in a H2-rich stream have been examined by means of operando-DRIFTS and -XANES (Cu K and Ce L3 edges) spectroscopies. The results reveal that CO oxidation activity is basically affected by CO2-induced hindrance of redox activity at the interface between dispersed copper oxide particles and the support as a consequence of carbonate formation. This appears influenced by support acid−base properties, as revealed by comparison of the obtained results with those observed over a different catalyst that was prepared by copper impregnation on pure ceria. CO2 is shown to affect negatively H2 oxidation activity, too, which is related to prevention of the extension of the reduction from the interface to the rest of the dispersed copper oxide particles, a process that provides active sites for such reaction.