The influence of CO 2 on NO reduction into N 2 over reduced ceria-based catalyst

•CO2 is a mild oxidant in the oxidation of oxygen defects of ceria with and without noble metal presence.•CO2 was not able to clean up the deposited carbon over the ceria surface which created by fuel pre-treatment.•Compared to CO2, NO was a much stronger oxidant. The deposited carbon can be oxidized during the NO exposure.•Traces of NO were able to compete with an excess of CO2 for oxygen vacancies.•NO is selectively converted to N2 in the presence of an excess of CO2.