A facile route for the fabrication of CeO₂ nanosheets via controlling the morphology of CeOHCO₃ precursors

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• 作者：C.R. Li ; ^{crli@zstu.edu.cn} ; Q.T. Sun ; N.P. Lu ; B.Y. Chen ; W.J. Dong
• 关键词：A1. Crystal structure ; A2. Hydrothermal crystal growth ; B1. Rare earth compounds ; B1. Oxides
• 刊名：Journal of Crystal Growth
• 出版年：2012
• 期刊代码：49_00220248
• 类别：ch
• 出版时间：15 March, 2012
• 卷：343
• 期：1
• 页码：95-100
• 文件大小：1122 K

摘要

The morphology and size of the functional oxide rare earth material CeO₂ are crucial for its efficient applications. CeO₂ nanosheets, which are 30-50 nm in thickness and about 300 nm in the lateral direction, have been synthesized via controlling the morphology of CeOHCO₃ precursors by a facile hydrothermal technique. The dependences of morphologies and phase transitions of CeOHCO₃ precursors on reaction time, chemical compositions are investigated in detail. Results show that the precursors exhibit changes both in morphology and phase structure as reaction time elongated. One-dimensional nanowire morphology with an orthorhombic phase structure is obtained when the reaction time is less than 3 h, while two-dimensional nanosheet with a hexagonal phase structure is formed when the reaction time is more than 9 h. The detailed transition process is recorded by snapshots of products between 3 and 9 h. Experimental results reveal that the amount of acetic acid is a key parameter for the nucleation and crystal growth of CeOHCO₃ nanosheets. A defect driven dissolving and recrystallization mechanism is proposed for the phase and morphology transition behavior of the precursors. The CeO₂ nanosheets are obtained after thermal decomposition of the precursors. Compared to the nanodisk, the CeO₂ nanosheets show a blue shift in the UV-Vis absorption spectra due to the quantum confinement effect.