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.