硅源加入方式对Fe3O4/SiO2核壳结构制备的影响及磁性能研究

表面包覆惰性层是解决四氧化三铁(Fe3O4)粒子团聚、易氧化、亲水性差等问题的一种有效方法,但惰性层的引入一般会导致包覆后样品磁性能下降,从而限制了Fe3O4的应用.以正硅酸乙酯(TEOS)和氨水为原料,制备了具有良好磁响应性的Fe3O4/SiO2核壳结构.样品的结构、形貌、尺寸和表面吸附官能团采用X-ray粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和红外光谱(FTIR)等测试手段进行了表征.研究发现,TEOS加入方式影响SiO2层生长过程,从而影响包覆的均匀程度.Fe3O4/SiO2核壳结构表现出顺磁性和良好的磁响应性(52emu/g).

Influence of adding method on the synthesis of Fe3O4/SiO2 core-shell structures and magnetic property study

The inert layer coated on the surface of magnetite(Fe3O4) could improve its hydrophilic property and prevent the agglomeration and oxidation of Fe3O4 particles.However,the inert layer could reduce the magnetic property of Fe3O4.In this study,magnetic Fe3O4/SiO2 core-shell structures were synthesized using tetraethyl orthosilicate(TEOS) and NH3·H2O as starting materials.Their structure,morphology,size,and functional groups were investigated by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and Fourier transform infrared(FTIR) spectroscopy.The adding methods of TEOS on the preparation of the Fe3O4/SiO2 core-shell structures were investigated.The magnetic measurements indicated that the Fe3O4/SiO2 core-shell structures showed ferromagnetic property and the magnetic saturation value slightly decreased after coated the silica layer(52emu/g).