AgI/AgCl/H2WO4 Double Heterojunctions Composites: Preparation and Visible-Light Photocatalytic Performance

AgI/AgCl/H2WO2 double heterojunctions photocatalyst was prepared via deposition-precipitation followed by ion exchange method. The structure, crystallinity, morphology, chemical content and other physical-chemical properties of the samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL). The photocatalytic activity of the AgI/AgCl/H2WO4 was evaluated by degrading methyl orange (MO) under visible light irradiation (lambda > 400 nm). The double heterojunctions photocatalyst displayed more efficient photocatalytic activity than pure AgI, AgCl, H2WO4 and AgCl/H2WO4. Based on the reactive species and energy band structure, the enhanced photocatalytic activity mechanism of AgI/AgCl/H2WO4 was discussed in detail. The improved photocatalytic performance of AgI/AgCl/H2WO4 double heterojunctions could be ascribed to the enhanced interfacial charge transfer and the inhibited recombination of electron-hole pairs, which was in close relation with the AgI/AgCl/H2WO4 heterojunctions formed between AgI, AgCl and H2WO4.