Preferential oxidation of CO in rich H2 over CuO/CeO2: Details of selectivity and deactivation under the reactant stream

A CuO/CeO2 catalyst is examined with respect to its performance for preferential oxidation of CO in H2-rich streams. Catalytic activity results are explained on the basis of characterization by operando-DRIFTS and complemented with the analysis of redox properties by electron paramagnetic resonance (EPR) and X-ray photoelectron spectra (XPS). General catalytic activity features are accounted for by comparative analysis of the activities for individual CO and H2 oxidation, for which similar CuO and CeO2 interfacial active sites appear to be involved. An interesting particularity is related to observation of a low temperature hydrogen oxidation process in which CO apparently acts as gaseous promoter. A deactivation process taking place rapidly under the reactant stream is evidenced and attributed to accumulation of hydroxyls on the interfacial active sites and/or to copper sintering in the course of the run.