Effect of Mg Addition on the Physical and Catalytic Properties of Cu/CeO2 for NO + CO Reduction

Copper catalysts supported on magnesia promoted ceria are synthesized and used for NO reduction by CO. The supports and the subsequent Cu catalysts are prepared by citric acid sol–gel and impregnation methods, respectively. The results of N2-physisorption, XRD, EPR and TPR measurements indicate that the Mg addition promotes not only the dispersion of CuO, but also the formation of Cu–O–Ce solid solution. The highest amount of Cu–O–Ce solid solution is found in catalyst modified with 5 wt.% MgO. Based on the catalytic performance, two active sites for the reduction NO by CO are proposed: copper matrix and Cu–O–Ce solid solution. The former does not require the involvement of oxygen vacancy and is more active at low temperature range (T