Magnetically separable γ-Fe2O3@SiO2@Ce-doped TiO2 core–shell nanocomposites: Fabrication and visible-light-driven photocatalytic activity

Novel visible-light-induced γ-Fe2O3@SiO2@Ce-doped-TiO2 core–shell nanocomposite photocatalysts capable of magnetic separation have been synthesized by a facile sol–gel and after-annealing process. The as-obtained core–shell nanocomposite is composed of a central γ-Fe2O3 core with a strong response to external fields, an interlayer of SiO2, and an outer layer of Ce-doped TiO2 nanocrystals. UV–vis spectra analysis indicates that Ce doping in the compound results in a red-shift of the absorption edge, thus offering increased visible light absorption. We show that such a γ-Fe2O3@SiO2@Ce-doped-TiO2 core–shell nanocomposite with appreciated Ce doping amount exhibits much higher visible-light photocatalytic activity than bare TiO2 and undoped γ-Fe2O3@SiO2@TiO2 core–shell nanocomposite toward the degradation of rhodamine B (RhB). Moreover, the γ-Fe2O3@SiO2@Ce-doped-TiO2 core–shell nanocomposite photocatalysts could be easily separated and reused from the treated water under application of an external magnetic field.