Preparation of CdS–TiO2/Fe3O4 photocatalyst and its photocatalytic properties

The CdS modified TiO2/Fe3O4 photocatalysts were prepared by sol–gel and immersion methods. The morphological, structural and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), UV–Vis absorption spectra, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The TEM observation showed that the surface of magnetite particles (Fe3O4) were coated by CdS–TiO2 layer as loose clusters, and average diameter of composites particles was about 250 nm. UV–Vis absorption spectra indicated that CdS–TiO2/Fe3O4 composites had pronounced red-shift compared with that of TiO2/Fe3O4. The CdS–TiO2/Fe3O4 composites exhibit higher photocatalytic activity than pure TiO2 and TiO2/Fe3O4 for the degradation of Reactive Brilliant Red X-3B dye (X-3B) aqueous solution under simulated sunlight, and the optimum content of CdS is 1.0 % (mol ratio of CdS to TiO2). In addition, a gradual loss of photocatalytic activity can be observed in reusability test of CdS–TiO2/Fe3O4 composites, and degradation of X-3B reached still to 78.9 % after five runs.