An attempt to rank copper-based catalysts used in the CO-PROX reaction

Abstract

This work provides a comparison of the activities of copper-based catalysts in the preferential oxidation of CO in the presence of H2. The Liu–Flytzani-Stephanopoulos equation [Liu W, Flytzani-Stephanopoulos M. Total oxidation of carbon monoxide and methane over transition metal-fluorite oxide composite catalysts II. Catalyst characterization and reaction kinetics. J Catal 1995;153:317–332] was used to evaluate catalytic rate constants on the basis of the data reported by various groups and in some cases these data were found to be insufficient. Although the reaction rate constants obtained could in some cases be influenced by experimental artefacts, it was unambiguously established that the addition of modifiers (e.g. Zr, Sn, Co, etc.) to the copper–ceria catalysts does not produce any improvement in the catalytic activity of these catalysts and that chelating methods are the most appropriate procedures for the preparation of CO-PROX catalysts. Deactivation during the testing of catalysts has received little attention in the literature, and yet it is a potential source of uncertainty in the catalytic activities reported.