Preparation And Photocatalytic Performance Study Of Oxide Semiconductor/Silver Phosphate Composites

In this paper, silver nitrate, sodium phosphate, sodium dihydrogen phosphate were raw material and the double decomposition reaction was used to synthesize silver phosphate; the synthesis route was improved to enhance the catalytic activity of Ag₃PO₄. The Ag₃PO₄/WO₃ composite photocatalyst, including heterojunction structure, was prepared by in-situ precipitation route, what’s more, the impact of monomer photocatalyst ratio on photocatalytic properties of composite photocatalyst was also studied; TiO₂ photocatalysis film was obtained by anodic oxidation method and Ag₃PO₄/TiO₂ was prepared by solution impregnation method on the base of titanium dioxide thin film; the impact of impregnation number on photocatalytic properties of composite photocatalytic film was discussed and the photovoltaic performance was tested by cyclic voltammetry. X-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, X-ray photoelectron spectroscopy, transmission electron microscope were carried out to investigate the as-obtained samples.The experimental results showed that:（1） The optimum conditions metathesis for the preparation of Ag₃PO₄ were as follows: time 15 min, silver nitrate concentration 0.100 mol/L, pH 6.5, temperature 25 ℃. As prepared Ag₃PO₄ with a size of about 200 nm has outstanding photocatalytic properties, under visible light irradiation, over 96% of methylene blue（10 mg?L-1, 50 m L） can be degraded by only 0.04 g photocatalyst in 25 minutes.（2） The in-situ precipitation route was used to synthesize the Ag₃PO₄/WO₃ composite photocatalyst, and because of the chemical bond was form between Ag₃PO₄ and WO₃, the photocatalytic activity and stability of Ag₃PO₄ were improved. The composite photocatalyst has the best photocatalytic properties when the monomer Ag₃PO₄ and WO₃ have a mass ratio of 4:1.（3） TiO₂ photocatalytic film prepared by anodic oxidation in different systems are anatase type and the TiO₂ nanotubes with thickness of about 1 μm and diameter of about 100 nm were prepared in organic solution.（4） Ag₃PO₄/TiO₂ photocatalytic film prepared by dipping method on the base of TiO₂ photocatalytic nanotubes can available a better photocatalytic properties and photocatalytic stability when the dipping test cycle six times. Cyclic voltammetry results showed that the composite photocatalytic film had a greater oxidation current than single TiO₂ film in NaHCO₃ system, indicating that the composite photocatalytic film with strong photocatalytic-oxidating activity can be used as an anode material of photoelectric catalytic reduction of CO₂.