Crystalline evolution of various CeO₂ morphology via a solvothermal method

Preparation of cerium compounds with different structures and morphology is still a challenge in powder synthesis. CeOHCO₃ and CeO₂ have received widespread attention because of their potential applications. In this study, a solvothermal method with one-step precipitation was used to synthesize CeO₂ with different structures and morphology without use of surfactant. The effects of different experimental conditions on the morphology of CeO₂ were investigated. Both X-ray diffraction and SAED patterns revealed that products changed from a single CeOHCO₃ phase to a mixture of CeOHCO₃ and CeO₂. A single CeO₂ phase could always be obtained from CeOHCO₃ by calcination in air at 673 K for 1 h. Moreover, the morphology of CeOHCO₃ was retained. Thus CeO₂ particles with different morphology, for example rod-like, prism-like, polygon-like, sphere-like, and cube-like, could be synthesized. Possible mechanisms of phase and morphology evolution are discussed.