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

摘要

Organic-inorganic composite materials have demonstrated many potential applications in environmental field. This paper presented a facile preparation method for gamma-Fe2O3/PMMA/S-TiO2 nanocomposite with core-shell structure and its application in degradation of phenanthrene under visible light irradiation. Firstly, gamma-Fe2O3/PMMA nanoparticles were synthesized by the modified-suspension-polymerization method. Then gamma-Fe2O3/PMMA/S-TiO2 core-shell nanocomposites were prepared by adding as-synthesized gamma-Fe2O3/PMMA nanoparticles into the sol solution formed by sol-gel method using tetra-butyltitanate 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 gamma-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 degrees C. UV-vis diffuse reflectance spectroscopy showed that gamma-Fe2O3/PMMA/S-TiO2 nanocomposite clearly exhibits the red-shift of the absorption edge compared with gamma-Fe2O3/PMMA/TiO2. The photocatalytic activity evaluation showed that the gamma-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 degrees C and the addition concentration of 1.0 g/L. Moreover, the nanocomposites have good recovery ability by the recovery experiment. (C) 2016 Elsevier Ltd. All rights reserved.