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Template‐Free Synthesis and Mechanistic Study of Porous Three‐Dimensional Hierarchical Uranium‐Containing and Uranium Oxide Microspheres
Author(s) -
Wang Lin,
Zhao Ran,
Wang Congzhi,
Yuan Liyong,
Gu Zhanjun,
Xiao Chengliang,
Wang Shuao,
Wang Xinwei,
Zhao Yuliang,
Chai Zhifang,
Shi Weiqun
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201403724
Subject(s) - calcination , uranium , hydrothermal circulation , uranyl , materials science , chemical engineering , porosity , hydrothermal synthesis , uranyl nitrate , microstructure , oxide , nuclear chemistry , uranium oxide , inorganic chemistry , chemistry , catalysis , metallurgy , organic chemistry , composite material , engineering
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 UO 3 ⋅NH 3 ⋅5 H 2 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 (UO 2+ x , U 3 O 8 , and UO 3 ) were successfully synthesized.