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.