Synthesis of TiO2/SiO2@Fe3O4 magnetic microspheres and their properties of photocatalytic degradation dyestuff

The TiO2/SiO2@Fe3O4 photocatalysts were synthesized via two steps. First, the SiO2@Fe3O4 particles were synthesized using Fe3O4 as the core and tetraethoxysilane (TEOS) as silica source. Second, the anatase TiO2 was coated on the SiO2@Fe3O4 particle surface using tetrabutyl titanate (TBOT) as titanium source. The synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption techniques and vibration sample magnetometer (VSM). The catalytic activity of TiO2/SiO2@Fe3O4 catalysts for the photocatalytic degradation of Rhodamine (RhB) was evaluated under ultraviolet (UV) irradiation. The results indicated that the mean size of the 6%SiO2@Fe3O4 particles was about 75–80 nm and thickness of the homogeneous SiO2 layer was about 2–3 nm. The diameter of 50%TiO2/6%SiO2@Fe3O4 microspheres was about 100 nm and thickness of the homogeneous anatase TiO2 layer was about 8–10 nm. The saturation magnetization and specific surface area of 50%TiO2/6%SiO2@Fe3O4 catalysts were 48.6 emu/g and 495.3 m2/g, respectively. The 50%TiO2/6%SiO2@Fe3O4 microspheres exhibited the best photocatalytic performance. The conversion of RhB achieved up to 98.1% after 60 min UV irradiation, and the photocatalytic reaction apparent rate constant ka was 0.05288 min−1. After used for 8 times, it also maintained high degradation rate and catalyst recovery.

Graphical abstractThe core-shell TiO2/SiO2@Fe3O4 magnetic microspheres photocatalysts were synthesized by a simple sol–gel method. The magnetic microspheres possessed the higher BET surface area and the stronger superparamagnetism. The photocatalysts have an excellent photocatalytic performance for the photocatalytic oxidation degradation of Rhodamine and reusability.Figure optionsDownload full-size imageDownload high-quality image (176 K)Download as PowerPoint slideHighlights► Core-shell TiO2/SiO2@Fe3O4 magnetic microspheres photocatalysts were synthesized by a simple sol–gel method. ► The TiO2/SiO2@Fe3O4 possessed the high BET surface area up to 495.3 m2 g−1 and the strong superparamagnetism up to 48.6 emu/g. ► The TiO2/SiO2@Fe3O4 photocatalysts showed the excellent photocatalytic performance for the photocatalytic oxidation degradation of Rhodamine and the reusability.