Enhanced Photocatalytic Properties of Silver Oxide Loaded Bismuth Vanadate

In this work, BiVO4 powders were synthesized by a sol–gel method, and the BiVO4 gels with different calcination temperature were investigated by X-ray diffraction (XRD). Absorption range and band gap energy, which are responsible for the observed photocatalyst behavior, were investigated by UV/vis diffuse reflectance spectroscopy (DRS) for pure and silver oxide loaded BiVO4. Photocatalytic properties of the prepared samples were examined by studying the degradation of the methyl orange. When using NaClO2 as an electron acceptor, the possible photocatalytic mechanism has been discussed by photocatalytic reactions. With the help of electron acceptor, the results show clearly that the BiVO4 loaded silver oxide exhibited superior photocatalytic activity in simulated dye wastewater treatment.

It is shown that the VO4 tetrahedra do not share corners or edges in BiVO4. It means that the free electrons have to hop between VO4 tetrahedra, this leads to the poor electron transport properties. When the semiconductor was irradiated by simulate visible-light, as long as the photon energy is greater or equal than the semiconductor band gap, the valence band electron is stimulated to the conduction band, which left photo-generated holes in the valence band, while electrons generated in the conduction band were captured. As shown in figure (a) and (b), silver oxide was loaded on the surface of BiVO4, which acts as an electron acceptor. In addition, the BiVO4 loaded silver oxide improved the absorption of visible light. So enhancing the photocatalytic properties is obtained.Figure optionsDownload as PowerPoint slide