Study of the surface and redox properties of ceria–zirconia oxides

CeO2–ZrO2 oxides with different CeO2 content (1–12 wt%) were prepared by the impregnation method. The effects of CeO2 content, calcination temperature and interaction between the components on the structure and reductive properties of CeO2–ZrO2 oxides were evaluated by using different techniques such as XRD, DRS, FTIR, Raman, XPS, TGA and TPR. Spectroscopic data showed that the tetragonal phase of zirconia is preserved in all CeO2–ZrO2 oxides, although they retain a high number of defect sites caused by a strong interaction between zirconia and cerium oxide species. An enrichment of the zirconia surface with a fluorite structure of CeO2 is observed for the CeO2–ZrO2 oxide with the highest CeO2 content (12 wt%). The samples subjected to consecutive reduction–oxidation cycles at different temperatures showed good redox properties related to the increase of oxygen mobility. It was concluded that these CeO2–ZrO2 oxide systems, displaying high surface and good thermal stability, are similar to chemically mixed oxides due to the strong interaction between the zirconia carrier and deposited ceria.

The effect of CeO2 content, calcination temperature and interaction between components on the structure and redox properties of CeO2–ZrO2 oxides was evaluated. At the highest CeO2 loading (12 wt%) and after high temperature treatment of 1073 K an enrichment of the zirconia surface with a fluorite structure of CeO2 is observed in the figure. XRD of CeO2, ZrO2 and CeO2–ZrO2 oxides with different CeO2 content after temperature treatment at 823 (A) and 1073 K (B). Figure optionsDownload as PowerPoint slide