Magnetically separable γ-Fe _2O _3@SiO _2@Ce-doped TiO _2 core-shell nanocomposites: Fabrication and visible-light-driven photocatalytic activity

摘要

Novel visible-light-induced γ-Fe _2O _3@SiO _2@Ce-doped-TiO _2 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-Fe _2O _3 core with a strong response to external fields, an interlayer of SiO _2, and an outer layer of Ce-doped TiO _2 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-Fe _2O _3@SiO _2@Ce-doped-TiO _2 core-shell nanocomposite with appreciated Ce doping amount exhibits much higher visible-light photocatalytic activity than bare TiO _2 and undoped γ-Fe _2O _3@SiO _2@TiO _2 core-shell nanocomposite toward the degradation of rhodamine B (RhB). Moreover, the γ-Fe _2O _3@SiO _2@Ce-doped-TiO _2 core-shell nanocomposite photocatalysts could be easily separated and reused from the treated water under application of an external magnetic field.