The staggered heterojunction of CeO2/CdS nanocomposite for enhanced photocatalytic activity

To modify the photocatalytic activity of CeO2, CdS nanoparticles was composited with CeO2 through a homogeneous precipitation method. The crystal structure, composition, morphology, and optical properties of CdS/CeO2 composite were analyzed in detail. The results found that CdS/CeO2 composite consisted of the cubic fluorite structure of CeO2 and wurtzite hexagonal structure of CdS. Meanwhile, TEM magnification of CdS/CeO2 composite exhibited clear lattice fringe corresponding to [hkl] plane of CeO2 and CdS. UV-visible absorption spectra showed that CdS extended the adsorption edge of the CdS/CeO2 composite to longer visible region, which related to the decrease of band gap. The coexistence of staggered type II band alignment in the CdS/CeO2 composite facilitated the charge separation of visible-excited electrons and holes, thereby decreasing the recombination and improving the efficient photocatalytic activity for methylene blue dye degradation, with the apparent rate constant (0.0102 min(-1)) which is about 7 times higher than that of pure CeO2 (k=0.0014 min(-1)).