Template‐Free Synthesis and Mechanistic Study of Porous Three‐Dimensional Hierarchical Uranium‐Containing and Uranium Oxide Microspheres |
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| Authors: | Dr Lin Wang Dr Ran Zhao Dr Cong‐zhi Wang Dr Li‐yong Yuan Dr Zhan‐jun Gu Dr Cheng‐liang Xiao Dr Shu‐ao Wang Dr Xin‐wei Wang Prof Yu‐liang Zhao Prof Zhi‐fang Chai Dr Wei‐qun Shi |
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| Institution: | 1. Key Laboratory of Nuclear Radiation and Nuclear Energy Technology and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (P.R. China), Fax: (+86)?10‐88235294;2. School of Radiological and Interdisciplinary Sciences, Soochow University, Suzhou 215123 (P.R. China);3. School of Advanced Materials, Peking University, Shenzhen Graduate School, Shenzhen 518055 (P.R. China) |
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| Abstract: | A novel type of uranium‐containing microspheres with an urchin‐like hierarchical nano/microstructure has been successfully synthesized by a facile template‐free hydrothermal method with uranyl nitrate hexahydrate, urea, and glycerol as the uranium source, precipitating agent, and shape‐controlling agent, respectively. The as‐synthesized microspheres were usually a few micrometers in size and porous inside, and their shells were composed of nanoscale rod‐shaped crystals. The growth mechanism of the hydrothermal reaction was studied, revealing that temperature, ratios of reactants, solution pH, and reaction time were all critical for the growth. The mechanism study also revealed that an intermediate compound of 3 UO3?NH3?5 H2O was first formed and then gradually converted into the final hydrothermal product. These uranium‐containing microspheres were excellent precursors to synthesize porous uranium oxide microspheres. With a suitable calcination temperature, very uniform microspheres of uranium oxides (UO2+x, U3O8, and UO3) were successfully synthesized. |
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| Keywords: | actinides oxides phase transitions porous structures uranium |
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