Preparation And Catalytic Performance Research Of Silver Bromide Composite Photocatalyst

In recent years,the requirements for environmental purification,especially sewage treatment have been continuously improved.Traditional water pollution treatment technologies have not been able to meet their needs well.Semiconductor photocatalytic technology has received widespread attention due to its advantages such as high efficiency and environmental friendliness,and shows great potential in solving the environmental problems currently facing.However,there are still some problems with the catalyst degradation of organic pollutants in water,such as weak light absorption capacity and low catalytic efficiency.Therefore,it is necessary to develop a photocatalytic material with good visible light response and excellent catalytic performance.In this paper,two heterojunction photocatalysts,rGO/AgBr and AgBr/Bi₂O₂CO₃,were prepared.The structure,morphology,optical properties and other properties of the prepared catalyst are determined by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and ultraviolet-visible diffuse reflection spectrum（UV-vis DRS）and other characteristics for analysis.Under the conditions of simulating sunlight,Rhodamine B（Rh B）was used as the target pollutant,and the prepared photocatalyst was used for degradation experiments to research its catalytic performance,and its degradation mechanism was further analyzed through capture experiments.The main research contents are as follows:1.A series of rGO/AgBr composite photocatalyst was prepared by solvothermal method using ethylene glycol as the solvent,KBr and AgNO₃ as raw materials,and adding a certain amount of GO.The results show that graphene and AgBr are successfully compounded,and the film-like substance（graphene）is evenly wrapped on the surface of irregular granular AgBr particles,forming a heterostructure,and this heterostructure is beneficial to increase the catalytic activity of rGO/AgBr composite photocatalyst.The research on catalytic degradation of Rh B shows that,the catalytic activity of the rGO/AgBr composite photocatalyst is significantly improved after loading graphene,and the photodegradation rate can reach almost 100%in 40minutes.Finally,the kinetics and possible mechanism of rGO/AgBr photocatalytic degradation of Rh B were investigated.2.Using PVP as a surfactant,and using Bi（NO₃）₃·5H₂O、C₃H₅Na₃O₇·2H₂O and urea as raw materials,a rose-like spherical Bi₂O₂CO₃ was prepared by hydrothermal method,and a series of AgBr/Bi₂O₂CO₃ composite photocatalysts were prepared by solvothermal method through compounding with different ratios of AgBr.The results showed that AgBr nanoparticles were successfully composited with rose-like spherical Bi₂O₂CO₃.Through the research on the degradation of Rh B,it is found that pure Bi₂O₂CO₃ has almost no catalytic activity,pure AgBr has better catalytic activity,and the photocatalytic activity of the AgBr/Bi₂O₂CO₃ composite photocatalyst is significantly improved compared to AgBr and Bi₂O₂CO₃,the photodegradation rate in60 minutes can reach almost 100%.Finally,the capture experiment was used to study the active groups that play a major role in the photocatalytic degradation of Rh B,and it is speculated that its degradation mechanism conforms to the Z-type degradation mechanism.