Fabrication of bifunctional titania/silica-coated magnetic spheres and their photocatalytic activities

A magnetic photocatalyst is prepared by coating a magnetic core with a dual layer of inert silica (SiO2) and photoactive titania (TiO2). The complete photoactive TiO2 shell is directly formed on the SiO2-coated magnetic spheres. Subsequent hydrothermal treatment improves the degree of crystallinity of TiO2. TiO2/SiO2-coated magnetic spheres show good photocatalytic activities in the degradation of methylene blue in the aqueous solution. The photocatalytic TiO2 surface shell is electrically insulated by the intermediate SiO2 layer from the magnetic core to maintain good photocatalytic activity of the TiO2 shell. The magnetic photocatalyst can be easily recovered by applying external magnetic field.