摘要
采用多步包覆法在自制的240nm的单分散SiO2微球表面进行β-FeOOH的包覆,在5wt%的NaOH溶液中去除核心SiO2后,得到β-FeOOH纳米结构空心微球。将单分散的β-FeOOH空心球作为内核,十六烷基三甲基溴化铵(CTAB)为模板剂,正硅酸乙酯(TEOS)为硅源,经水解缩聚反应得到空心核壳复合微球。在空气中焙烧(500℃,5h)对样品去除模板剂,并在还原气氛(5%H2/95%Ar,350℃,3h)下焙烧得到介孔SiO2/Fe3O4中空磁性复合微球。结果表明,所制得的介孔SiO2/Fe3O4中空磁性复合微球中的Fe3O4层厚度约60nm,是由Fe3O4纳米棒搭接而成的三维网络结构,复合微球的整体平均直径为390nm,比表面积较高约693m2·g-1,孔体积为0.63cm3·g-1,平均孔径为3.6nm,其饱和磁化强度可达13.6emu·g-1,同时较低的矫顽力(50Oe)有利于颗粒的再分散。
The home-made monodispersed SiO2 microspheres with uniform size（240 nm） were coated with β-FeOOH by a multistep coating technique.The silica shell of β-FeOOH hollow microspheres was coated on β-FeOOH hollow microspheres from simultaneous sol-gel polymerization of tetraethoxysilane（TEOS） in the presence of a cationic surfactant（cetyl trimethyl ammonium bromide;CTAB）.The α-Fe2O3/mesoporous SiO2 hollow spheres were prepared after removal of the organic group by calcinating at 500℃ for 5 h in reducing atmosphere（a flowing gas mixture of H2 and Ar（5%H2/95%Ar（V/V）,350 ℃,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 monodispersed and nearly uniform with an average diameter of 390 nm.BET calculation shows that the spheres have large surface area（693 m2·g-1）,average pore size of 3.6 nm and pore volume of 0.63 cm3·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.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2010年第10期1756-1760,共5页
Chinese Journal of Inorganic Chemistry
基金
国家杰出青年科学基金(No.50525413)
国家863计划(No.2009AA03Z213)资助项目
关键词
介孔
磁性
空心微球
mesoporous
magnetic
hollow microsphere
