Preparation and characterization of Fe₃O₄@TiO₂ core-shell magnetic nanomaterials

Core-shell magnetic Fe₃O₄@TiO₂ nanomaterials with different morphologies have been obtained by combining the sol-gel method and solvothermal method. The monodisperse Fe₃O₄ core was synthesized by solvothermal reaction, and the TiO₂ shell was derived using solvothermal reaction and sol-gel method with tetrabutyl titanate as the precursor. The morphology, structure and magnetic properties of Fe₃O₄@TiO₂ nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The results showed that Fe₃O₄ nanoparticles were coated by TiO₂, and Fe₃O₄@TiO₂ exhibited high degree of crystallinity, regular crystalline morphologies and excellent magnetism. These integrated features would make the Fe₃O₄@TiO₂ materials have attractive applications in areas of environmental purification, biomedical field, energy conversion and storage. In addition, the formation mechanism of TiO₂ shell was also proposed.