Fe_3O_4@SiO_2@TiO_2复合纳米结构的尺寸与磁性调控

Control of the size and magnetic property for Fe_3O_4@SiO_2@TiO_2 composite microstructures

采用共沉淀法和溶剂热法制备了不同尺寸的Fe_3O_4纳米粒子,通过Stber法和溶胶-凝胶法在Fe_3O_4磁核上包覆SiO_2和Ti O2壳层获得不同尺寸的Fe_3O_4@SiO_2@Ti O2复合纳米结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和振动样品磁强计(VSM)等对其结构、形貌和磁性进行了研究.结果表明,大尺寸复合纳米粒子包覆均匀,分散性好,饱和磁化强度较大,有利于TiO_2光催化剂的磁回收与再利用.

Fe3O4nanoparticles with different sizes were synthesized by the coprecipitation and hydrothermal methods.The preformed Fe3O4 magnetic particles are used as templates to grow sequential SiO2 coupling layer by Stber method and subsequent TiO2 layer by sol-gel reactions,leading to the Fe3O4@ SiO2@ TiO2 composite structures with different sizes.The structure,morphology and magnetic properties of these nanoparticles were characterized using X-ray diffractometer（ XRD）,Scanning Electron Microscope（ SEM）,Transmission Electron Microscope（ TEM） and Vibrating Sample Magnetometer（ VSM）.The composite structures with large size exhibit better coating uniformity,dispersion,and high saturation magnetization,which is more favorable for the magnetic recovery and reuse of TiO2 photocatalysts.