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 H-2-rich streams. Catalytic activity results are explained on the basis of characterization by operando-DRIFFS 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 H-2 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. (c) 2006 Elsevier B.V. All rights reserved.