Comparative study of photocatalytic activities of magnetically separable WO3/TiO2/Fe3O4 nanocomposites and TiO2, WO3/TiO2 and TiO2/Fe3O4 under visible light irradiation

In this study WO3/TiO2/Fe3O4 nanocomposite particles with different amount of WO3 content (1, 3, 5, 8 and 10 wt.%) were prepared via sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface areas, diffuse reflectance spectra (DRS) and the vibration sample magnetometry (VSM) were used to characterize the nanocomposites. The photocatalytic activity of the nanoparticles was tested by degrading direct blue 71 dye solution under visible light irradiation. The enhanced photocatalytic activity is attributed to the electron hole separation and transformation among the semiconductors. The effect of the initial dye concentration, catalyst dosage and the photocatalytic reaction apparent rate constant k(app) were also investigated. On the other hand the WO3/TiO2/Fe3O4 nanocomposites could be readily recovered from the reaction solution by using a permanent magnetic bar and their photocatalytic activity was studied after six cycles of repetitive recycling. Then, this nanocomposite can be used as highly efficient and reusable photocatalyst. (C) 2015 Elsevier Ltd. All rights reserved.