双功能Fe_3O_4/Au、Fe_3O_4/Au@SiO_2复合微球的构筑和磁学性质研究

Bifunctional Hybrid Microspheres Fe_3O_4/Au, Fe_3O_4/Au@SiO_2: Fabrication and Magnetic Properties

给出一种温和条件下构筑Fe3O4/Au,Fe3O4/Au@SiO2复合纳米结构材料的方法,并研究所得产物的光学、磁学性质。首先,用3-氨丙基三甲氧基硅烷(APS)对平均粒径300 nm的Fe3O4微球进行表面修饰使得其拥有大量的氨基官能团(-NH2),利用这些官能团末端的孤对电子可以共价吸附Au纳米粒子的特性,在一定条件下制备出Fe3O4/Au复合纳米结构材料,不经过任何表面处理利用St?ber方法在室温条件下对其进行SiO2包覆,得到Fe3O4/Au@SiO2复合材料。借助场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)对产物的形貌和结构进行表征,并利用紫外-可见(Uv-Vis)分光光度计和超导量子干涉仪(SQUID)对产物的光学和磁学性质进行分析。结果表明,由于所含金浓度太低,Fe3O4/Au复合材料并没有显示金纳米粒子的特征表面等离子体共振吸收峰;Fe3O4/Au,Fe3O4/Au@SiO2复合纳米结构均显示出超顺磁性和高的饱和磁化率。

A facile route to prepare Fe3O4/Au, Fe3O4/Au@SiO2 hybrid nanostructures was reported, and the related properties such as magnetism and optics of the products were explored. Firstly, 3-aminopropyltrimethoxysilane （APS） was utilized to modify the surface of Fe3O4 microspheres with a mean size of 300 nm, which made the surface of these microspheres possess lots of amino groups （-NH,）. Subsequently, Fe304/Au hybrid nanostructures could be fabricated for the property that Au nanoparticles can be adsorbed covalently by the terminal lone pair electrons from amino group under certain conditions. Lastly, such Fe3O4/Au hybrid structures were coated with SiO2 to form Fe3O4/Au@SiO2 components by the Strber method at room temperature without any surface modification. The morphologies and structures of the products were characterized using field emission scanning electron microanalyzer （FESEM） and transmission electron microscopy （TEM）, respectively, meanwhile, optical and magnetic properties of the products were investigated in detail in this paper, the results show the surface plasma absorbance of Au was invisible in Fe3O4/Au hybrid nanostructures due to low content of Au, both of Fe3OV Au, Fe3O4/Au@SiO2 hybrid nanostructures show superparamagnetism and high saturation magnetization values.