Catalytic processes during preferential oxidation of CO in H2-rich streams over catalysts based on copper–ceria

Nanostructured catalysts based on combinations between oxidised copper and cerium entities prepared by two different methods (impregnation of ceria and coprecipitation of the two components within reverse microemulsions) have been examined with respect to their catalytic performance for preferential oxidation of CO in a H2-rich stream (CO-PROX). Correlations between their catalytic and redox properties are established on the basis of parallel analyses of temperature programmed reduction results employing both H2 and CO as reactants as well as by XPS. Although general catalytic trends can be directly correlated with the redox properties observed upon separate interactions with each of the two reductants (CO and H2), the existence of interferences between both reductants must be considered to complete details for such activity/redox correlation. Differences in the nature of the active oxidised copper–cerium contacts present in each case determine the catalytic properties of these systems for the CO-PROX process.