Cobalt supported on metal-doped ceria catalysts (M = Zr, Sn and Ti) for NO oxidation

Abstract

A series of ceria oxides doped with 20 mol% of Zr, Sn and Ti were prepared by a citric sol–gel method throughout the thermal decomposition of the corresponding metallic propionates. Furthermore, cobalt oxides were loaded on the supports by a one-step sol–gel method. The results showed a solid solution when doping with Zr and Ti and SnO₂ surface segregation in the case of Sn. We demonstrated that cobalt dispersion states were influenced by the doping metals. The Ce–Co metal-oxide catalyst possessed a higher amount of finely dispersed cobalt species, more oxygen vacancies and excellent redox ability. These features may be responsible for improving the catalytic activity of Ce–Co metal-oxides for NO oxidation.