Template-Free Synthesis and Mechanistic Study of Porous Three-Dimensional Hierarchical Uranium-Containing and Uranium Oxide Microspheres
Template-Free Synthesis and Mechanistic Study of Porous Three-Dimensional Hierarchical Uranium-Containing and Uranium Oxide Microspheres
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多孔三维多级含铀及氧化铀微球的无模板合成及机理研究
DOI：
10.1002/chem.201403724
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Shi Wei-qun
中科院分区：
文献类型：
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作者：
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
以六水合硝酸铀酰、尿素和甘油分别作为铀源、沉淀剂和形状控制剂，通过简便的无模板水热法成功合成了一种具有海胆状分级纳米/微米结构的新型含铀微球。合成的微球通常尺寸为几微米，内部多孔，其外壳由纳米级棒状晶体组成。研究了水热反应的生长机理，揭示了温度、反应物比例、溶液pH值和反应时间对于生长都至关重要。机理研究还表明，首先形成中间化合物 3 UO3⋅NH3⋅5 H2O，然后逐渐转化为最终的水热产物。这些含铀微球是合成多孔氧化铀微球的优异前体。在合适的煅烧温度下，成功合成了非常均匀的铀氧化物微球（UO2+x、U3O8和UO3）。
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.