Synthesis of magnetically separable Sn doped magnetite/silica core–shell structure and photocatalytic property

Sn doped Fe3O4/SiO2 core–shell structures with the magnetic and photocatalytic properties have been successfully synthesized using Fe3O4 microspheres as the precursor. The morphology, phase and structure of the bifunctional products were investigated by X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy. The effects of the amount and hydrolysis rate of tetraethyl orthosilicate on the preparation of the Fe3O4/SiO2 core–shell structures were investigated. Low concentration and slow hydrolysis rate of tetraethyl orthosilicate were useful to obtain the uniform silica coated Fe3O4. The magnetic measurements indicated that the Sn doped Fe3O4/SiO2 core–shell structures showed ferromagnetic property and the magnetic saturation value slightly decreased after coated the silica layer. The magnetic Sn doped Fe3O4/SiO2 core–shell structures exhibited good photocatalytic activity in the degradation of methyl orange and could be separated by applying an appropriate magnetic field.