Ce³⁺-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 m² 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 CeO₂. 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 Ce³⁺. Moreover, O₂-pulse adsorption analyses demonstrated a significant oxygen adsorption capacity exceeding 268 μmol-O g^-1 at 400 °C owing to its high contents of Ce³⁺ species.