Catalysts of ceria supported on copper-chromium oxide: Ceria promotion of the CO-PROX activity

Abstract A copper-chromium mixed oxide with Cu:Cr 1:2 ratio has been prepared by a microemulsion method and employed as support of CeO2 in different amounts from 5 to 80 wt%. The catalysts have been characterized by XRD, HRTEM/XEDS, H2-TPR and XPS. The characterization results have been examined in correlation with their catalytic properties for the CO-PROX process complemented by operando-DRIFTS. The catalysts are formed by composites of CuCr2O4 and CuO on which aggregates of CeO2 nanoparticles are dispersed. Incorporation of CeO2 onto the CuCr mixed oxide appreciably enhances the CO-PROX performance of the catalyst. This is related to a promotion of the generation and stabilization of active partially reduced copper sites during the course of the interaction of the catalysts with the reactant mixture and which are evidenced to be formed on both CuCr oxide and CeO2 components of the catalysts.