Controllable synthesis of spherical cerium oxide particles

Spherical CeO₂ submicron particles were synthesized by a facile PVP-assisted hydrothermal method. By the analysis of XRD, FESEM, TEM and selected area electron diffraction (SAED), we confirmed that the as-obtained spherical CeO₂ particles were formed by the oriented aggregation of fluorite CeO₂ nanocrystals. The formation mechanism was discussed by varying synthetic parameters such as reaction temperature, and the concentration of cerium salt. In our synthetic process, Ce(NO₃)₃·6H₂O was first hydrolyzed to rod-like organic cerium salt by the assistance of PVP, then the organic cerium salt was decomposed into CeO₂ nanocrystals. Finally, spherical CeO₂ particles were formed by the oriented aggregation of these CeO₂ nanocrystals through the interaction between the same crystal planes of different nanocrystals and the assistance of PVP.