Preparation of tungsten-doped BiVO₄ and enhanced photocatalytic activity

W-doped BiVO₄ samples have been successfully synthesized by a simple sol–gel technique, which involved the formation process of precursor and the subsequent calcination treatment. The incorporation of W ions into BiVO₄ was detected by X-ray diffraction. Through X-ray photoelectron spectroscopy (XPS) and defect reactions, the tungstic ions should be responsible for the enhancement of decolorization due to reducing the consumption of photogenerated electrons. Also, the XPS signal of O 1s was investigated, indicating that doped W species greatly improve the hydroxyl and H₂O adsorption on the surface of W-doped BiVO₄. In addition, the photoluminescence experiments indicate the enhanced separation of electron–hole pairs in comparison with pure BiVO₄