Preparation and characterization of TiO2-SiO2-Fe3O4 core-shell powders in nano scale

TiO2/SiO2/Fe3O4 nanoparticles have bigger specific area which can greatly increase the efficiency of photo-catalysis.The TiO2/SiO2/Fe3O4 particles in nano scale were prepared with reduction method at high temperature in this paper,and their morphology,particle size and magnetic property were characterized by transmission electron microscope （TEM）,Xray diffraction （XRD） and magnetometer.The results show that the grain sizes of Fe3O4,SiO2-Fe3O4 and TiO2-SiO2-Fe3O4 particles were 50 nm,70 nm and 120 nm,respectively.With the modification of SiO2,Fe3O4 magnetic cores are protected from oxidation.Moreover,by the addition of TiO2 function layer,TiO2-SiO2-Fe3O4 functional nanoparticles,with the saturation magnetization density of 34.1 emu/g,is magnetically recoverable.The processes of this method are so simple that the nanoparticles can be produced in large quantity.