核壳结构Fe_3O_4@SiO_2纳米粒子的制备及表征

Preparation and characterization of core-shell structure Fe_3O_4@SiO_2 nanoparticles

为丰富Fe_3O_4磁性纳米粒子在生物医学领域的应用,通过共沉淀法制备Fe_3O_4纳米粒子,经柠檬酸三钠修饰后,采用改进的Stber法成功在Fe_3O_4纳米粒子表面包覆上SiO_2,制备出核壳结构Fe_3O_4@SiO_2纳米粒子。使用扫描式电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、振动样品磁强计对制备的Fe_3O_4@SiO_2纳米粒子进行表征。结果表明:制备的Fe_3O_4@SiO_2纳米粒子较Fe_3O_4纳米粒子分散性有明显的提高,平均粒径在65 nm左右,饱和比磁化强度为10.26 A·m^2/kg,仍具有良好的超顺磁性。

In the paper, emphasis is put on the synthesis and characterization of Fe3O4@SiO2 core/shell structured nanoparticles. Superparamagnetic Fe3O4 nanoparticles are prepared by co-precipitation method and then, silica is coated on the surface of the magnetite nanoparticles by modified St ber method. Subsequently, the nanocomposite samples are characterized by scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and vibrating sample magnetometer. The results reveal that the Fe3O4 and Fe3O4@SiO2 nanoparticles have an average size of 15 nm and 65 nm diameters, respectively. Moreover, the nanocomposites are monodisperse and uniformly spherical with well-defined shell-core structures and exhibit superparamagnetic characteristics. Meanwhile, spinel structure for the magnetite particles coated by silica is revealed by powder X-ray diffraction measurements.