Preparation And Visible Photocatalysis Of Ag₃PO₄/Bi₁₂O₁₅Cl₆ Composite Photocatalysts

Photocatalytic oxidation method is energy efficient,no secondary pollution and high degradation efficiency.It is often used to treat refractory wastewater,such as printing and dyeing wastewater.The preparation of high efficiency green visible light catalyst is a hot topic.Bi₁₂O₁₅Cl₆mainly absorbs ultraviolet light,but the absorption rate of visible light is low,so the efficiency of visible photocatalysis is not high.Therefore,the Bi₁₂O₁₅Cl₆catalytic activity is improved by loading the Ag₃PO₄by in situ deposition after hydrothermal synthesis.The effect of hydrothermal time,temperature and composite ratio on the photocatalytic activity of the composite photocatalyst was studied using AO7 as the target substrate.It was concluded that the optimum preparation condition for photocatalytic activity was hydrothermal 12 h,temperature 180℃,n（Ag）:n（Bi）is10%（calculationed by adding raw materials）.By XRD,XPS,BET,TEM,SEM,the morphology,surface properties and optical properties of the materials were characterized and analyzed.The results showed that the Ag₃PO₄and Bi₁₂O₁₅Cl₆were well compounded,Infrared absorption range was expanded,the band gap was reduced,the specific surface area was increased,and the catalytic activity was improved.The effects of the dosage of Ag₃PO₄/Bi₁₂O₁₅Cl₆composite photocatalyst,the initial concentration of substrate and the p H、salt efficiency on the degradation efficiency were investigated,and the stability the composite photocatalyst and the preliminary kinetic analysis were carried out.When catalyst dosage is 1.0 g/L,substrate concentration is 1.5 mg/L,p H at 7,The efficiency of catalytic degradation of AO7 was 95.4%.There was still 66.3%degradation rate after 6 cycles.The effect of salt effect is small.The active groups in the photocatalytic reaction are.O₂-and h⁺.According to the analysis,the band structure of the catalyst is calculated,and it is speculated that the TypeⅡheterojunction structure may be formed between the composite semiconductors.The possible path of Ag₃PO₄/Bi₁₂O₁₅Cl₆degradation of AO7 was inferred by LC-MS detection of the intermediate products of the reaction system.