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摘要:
The home-made monodispersed SiO2 microspheres with uniform size (240 nm) were coated with beta-FeOOH by a multistep coating technique. The silica shell of beta-FeOOH hollow microspheres was coated on) beta-FeOOH hollow microspheres from simultaneous sol-gel polymerization of tetraethoxysilane(TEOS) in the presence of a cationic surfactant (cetyl trimethyl ammonium bromide; CTAB). The alpha-Fe2O3/mesoporous SiO2 hollow spheres were prepared after removal of the organic group by calcinating at 500 degrees C for 5 h in reducing atmosphere (a flowing gas mixture of H-2 and Ar (5%H-2/95%Ar (V/V), 350 degrees C, 3 h)) to produce the Fe3O4/mesoporous SiO2 hollow spheres. The results indicate that in the Fe3O4/mesoporous SiO2 hollow spheres, the Fe3O4 layers of about 60 nm are constructed with Fe3O4 nanorods interconnected. The composite hollow spheres are well monodispersecl and nearly uniform with an average diameter of 390 nm. BET calculation shows that the spheres have large surface area (693 m(2).g(-1), average pore size of 3.6 nm and pore volume of 0.63 cm(3).g(-1). Magnetic characterization shows that the Fe3O4/mesoporous SiO2 hollow spheres have magnetization saturation value of 13.6 emu .g(-1). The magnified hysteresis loop confirms the low coercive force (50 Oe) of the particles favorable for redispersion.
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来源 :
CHINESE JOURNAL OF INORGANIC CHEMISTRY
ISSN: 1001-4861
年份: 2010
期: 10
卷: 26
页码: 1756-1760
0 . 7 0 0
JCR@2022
ESI学科: CHEMISTRY;
JCR分区:4
中科院分区:4