Visible-light-responsive γ-Fe2O3/PMMA/S-TiO2 core/shell nanocomposite: Preparation, characterization and photocatalytic activity

Organic-inorganic composite materials have demonstrated many potential applications in environmental field. This paper presented a facile preparation method for γ-Fe2O3/PMMA/S-TiO2 nanocomposite with core-shell structure and its application in degradation of phenanthrene under visible light irradiation. Firstly, γ-Fe2O3/PMMA nanoparticles were synthesized by the modified-suspension-polymerization method. Then γ-Fe2O3/PMMA/S-TiO2 core-shell nanocomposites were prepared by adding as-synthesized γ-Fe2O3/PMMA nanoparticles into the sol solution formed by sol-gel method using tetrabutyltitanate as Ti source and thiourea as sulfur source. The characterization result of the obtained products by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy indicated that the layer of sulfur doped titania was successfully coated onto the surface of γ-Fe2O3/PMMA nanoparticles. Thermogravimetry (TG) analysis presented that the layer of sulfur doped TiO2 could efficiently reduce the decomposition of polymethylmethacrylate (PMMA) even at higher temperature up to 500 °C. UV–vis diffuse reflectance spectroscopy showed that γ-Fe2O3/PMMA/S-TiO2 nanocomposite clearly exhibits the red-shift of the absorption edge compared with γ-Fe2O3/PMMA/TiO2. The photocatalytic activity evaluation showed that the γ-Fe2O3/PMMA/S-TiO2 nanocomposite exhibited the best photocatalytic activity for degradation of phenanthrene under the conditions of 0.8 mol% of sulfur doping, calcination temperature at 300 °C and the addition concentration of 1.0 g/L. Moreover, the nanocomposites have good recovery ability by the recovery experiment.