Research On Visible Light Photocatalysts Of AgX(X=Cl/Br) Modified Hydrotalcite

In the face of rapid economic development today,the demand for energy is also increasing year by year,the earth on which we live will gradually face the solstice growth of various environmental pollution problems,seriously affecting the natural ecological environment and people’s health.In recent years,photocatalytic technology has gradually become a new research direction in the field of environmental chemical industry in terms of environmental pollution and treatment.As for traditional photocatalysts such as Ti O₂ and Zn O,they can only be driven by ultraviolet light,which limits their practical application.Now people will pay more attention to catalysts driven by visible light,and a variety of new visible catalysts have been developed.Due to the exchangeability of anions between hydrotalcite layers,the colligation of main plate cations and the recombination of the structure,it has attracted much attention in the fields of catalysis and adsorption.Nowadays,it is used in photocatalysis field continuously as photocatalyst.However,hydrotalcite-based photocatalysts have large band gap energy and can only be driven by visible light.The visible light response can be expanded by ion doping or combining with other narrow-gap semiconductor catalysts.AgX（X=Cl,Br）is a widely used photosensitive material.The light absorption range can be extended to the visible light range,and its application in the field of photocatalysis has been gradually concerned by people.Because individual AgX photocatalytic degradation of performance is not very ideal,but if the hydrotalcite as the carrier,synthesize AgX load with composite material,research shows that the cycle of AgX stability will be improved,and composite materials with the decentralized will appear to improve phenomenon,on the rate will greatly improve the degradation of organic matter,spectral response range will be expanding,achieve the goal of modified composite photocatalytic performance.AgX（X=Cl,Br）composite ZnAl-LDH was used in this paper,the preparation of different load of AgX/ZnAl-LDH visible light catalyst,using XRD,SEM,TEM and BET,Uv-vis DRS,XPS,the characterization of samples,this paper discusses the AgX（Cl/Br）load in ZnAl-LDH structure and the influence of visible light catalytic properties,examines the photocatalytic reaction conditions to light catalytic effect,analyzes the dynamics characteristics of methyl orange interpretation process,and discusses the mechanism of photocatalytic degradation,get the following conclusions:（2）The visible light catalytic degradation efficiency of AgBr supported ZnAl-LDH photocatalyst was superior to that of AgCl supported ZnAl-LDH photocatalyst.Under the same load and degradation reaction conditions,the degradation rate of Ag/AgBr/ZnAl-LDH photocatalyst was much higher than that of Ag/AgCl/ZnAl-LDH photocatalyst.（3）the photocatalytic mechanism of a preliminary study results show that in the process of photocatalytic degradation of h⁺and·O₂^-major oxidation,Ag⁰ on the surface of the catalyst for light excitation of electron and hole center,under visible light irradiation,Ag⁰ produce light electronic-hole,light electron transfer to the surface of AgCl,respectively to form active free radicals,·O₂^-and·Cl,and oxidation of methyl orange,while ZnAl-LDH provides a carrier of load,Ag/AgCl by OH^-fixed Ag/AgCl particles.