Electronic excitation in a catalytic support oxide, CeO2 Original Research Article

X-ray resonant Raman scattering (XRRS) measurements were performed on a single crystal of ceria, CeO2, near the Ce LIII edge. Ceria is an important component of automotive catalytic converters, and helps to maintain the oxygen pressure in the vicinity of metal catalysts through the valence change Ce4+↔Ce3+. The XRRS spectra show rich features of electronic excitations in ceria involving various f state occupations of cerium that change with temperature and/or surface composition. Determining the electronic process that leads to valence change would facilitate the understanding of the buffering function of ceria.