Effects of surface area and oxygen vacancies on ceria in CO oxidation: Differences and relationships

Many properties of ceria, such as surface area, defects, and exposed crystal faces, were found to influence the CO oxidation performance of the ceria. Nevertheless, the relations of these properties, which will facilitate the understanding of the catalytic role of ceria in CO oxidation, have not been Studied. In this study, the ceria catalysts, HY and CA, were synthesized by hydrothermal method and citric acid sol-gel method, respectively, and the difference in the CO oxidation performance of them was studied using kinetics analysis. Results of temperature-programmed experiments and pulse experiment indicated the lattice oxygen extraction was the rate-determining step (RDS) in the CO oxidation on HY and CA catalysts. The RDS was influenced predominantly by the amount of the active lattice oxygen and the rate of oxygen migration on the catalyst, which were related to the surface area and oxygen vacancies in the catalyst. (C) 2009 Elsevier B.V. All rights reserved.