Z-scheme CdS-Au-BiVO4 with enhanced photocatalytic activity for organic contaminant decomposition

A Z-scheme heterogeneous photocatalyst CdS-Au-BiVO 4 was synthesized for the first time by photo-reduction and deposition-precipitation methods. The microstructures and optical properties of the as-prepared samples were investigated by means of scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS). Due to the oriented accumulation of electrons on the {010} facets of BiVO 4 crystals, Au nanoparticles were successfully anchored on the {010} facets of BiVO 4 crystals via the photo-reduction process. CdS was further selectively deposited on the surface of Au nanoparticles, benefitting from the strong S-Au interaction. Photocatalytic degradations of tetracycline and Rhodamine B indicated that CdS-Au-BiVO 4 exhibits much higher photocatalytic activity than BiVO 4 , Au-BiVO 4 , and CdS-BiVO 4 . Radical trapping experiments confirmed that in the case of CdS-Au-BiVO 4 , the main reactive species responsible for organic contaminant degradation are h + , &z.rad;OH, and &z.rad;O 2 − , while only h + can be produced in the case of CdS-BiVO 4 . Based on the photoelectrochemical analysis and radical trapping experiments, it can be deduced that the Z-scheme structure of CdS-Au-BiVO 4 not only decreases the recombination rate of photo-generated carriers but also makes the holes and electrons keep a higher redox ability. A Z-scheme heterogeneous photocatalyst CdS-Au-BiVO 4 was synthesized for the first time by photo-reduction and deposition-precipitation methods.