Ce 3+ -enriched spherical porous ceria with an enhanced oxygen storage capacity.

Porous ceria was obtained using a unique solvothermal reaction in acetonitrile, applying high temperature and pressure. The resulting material comprised homogeneous and monodisperse spheres and exhibited an extremely large surface area of 152 m 2 g -1 . From catalytic performance evaluation by vapor- and liquid-phase reactions, the synthesized porous ceria showed superior and different reaction activity compared with commercial CeO 2 . To examine the origin of the reaction activity of the present porous ceria, synchrotron hard X-ray photoelectron spectroscopy (HAXPES) measurements were carried out. The systematic study of HAXPES measurements revealed that the obtained porous ceria with the present solvothermal method contained a very high concentration of Ce 3+ . Moreover, O 2 -pulse adsorption analyses demonstrated a significant oxygen adsorption capacity exceeding 268 μmol-O g -1 at 400 °C owing to its high contents of Ce 3+ species.