Wang Lin, Zhao Ran, Wang Cong-Zhi, Yuan Li-Yong, Gu Zhan-Jun, Xiao Cheng-Liang, Wang Shu-Ao, Wang Xin-Wei, Zhao Yu-Liang, Chai Zhi-Fang, Shi Wei-Qun
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.
Chemistry. 2014 Sep 22;20(39):12655-62. doi: 10.1002/chem.201403724. Epub 2014 Aug 14.
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 H2 O 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 , U3 O8 , and UO3 ) were successfully synthesized.
