Research On Plasma Treatment And Application Of BiOBr Surface

Environmental pollution and resource shortage are the two major problems facing human society today.Photocatalytic technology is one of the effective methods to solve these two problems.As a new type of photocatalyst,BiOBr photocatalyst has the characteristics of unique layered structure,suitable forbidden band width and strong light absorption ability,which gives BiOBr excellent photocatalytic performance.It is a very valuable photocatalyst material.However,BiOBr has the disadvantage of low photo-generated carrier separation and transfer efficiency in the photocatalytic process.This limits the photocatalytic performance and practical application of BiOBr.In order to improve the photocatalytic performance of BiOBr photocatalyst,we modified the samples by low-temperature plasma treatment in different atmospheres.Through a series of characterization and testing,the morphological structure,element composition,and photoelectric characteristics of the modified sample were analyzed.Through the experiment of degradation of tetracycline(TC)under visible light,the photocatalytic performance of the sample was analyzed.And the mechanism of the photocatalytic process was initially explored.The specific research content is as follows:(1)Study on the performance of BiOBr treated with argon plasma.BiOBr nanosheets were synthesized by a simple solvothermal method,and treatment of BiOBr by argon plasma.The argon plasma will etch the sample and introduce oxygen vacancies into the sample.Using XRD,SEM,TEM,XPS,EPR,UV-vis DRS and EIS,the morphology,structure,element composition and photoelectric properties of the samples were analyzed.The photocatalytic ability and stability of the samples were characterized by the degradation of TC by visible light.The research results show that the presence of oxygen vacancies can increase the visible light absorption of the sample and reduce the band gap of the sample.The sample treated with argon plasma for 5 min has the best photocatalytic activity.Under visible light,75.64% of tetracycline is degraded within 2 h.(2)Study on the performance of BiOBr treated with nitrogen plasma.The BiOBr is modified by nitrogen plasma treatment,N element is doped into the crystal lattice of the sample,and oxygen vacancies are introduced into the sample at the same time.A variety of methods are used to analyze the morphology,element composition,photoelectric performance,photocatalytic ability and stability of the sample.The research results show that the doping of lattice N can make the absorption edge of the ultraviolet-visible diffuse reflectance spectrum of the sample red-shift,and enhance the visible light absorption of the sample.Among them,the sample treated with nitrogen plasma for 30 min had the best photocatalytic performance.Under visible light irradiation,79.35% of tetracycline was degraded after 2 h.(3)Study on the performance of BiOBr treated with nitrogen/argon plasma.The sample is processed by the plasma of the mixed gas of nitrogen and argon,and the N element is simultaneously doped into the crystal lattice and the gap of the sample.A variety of methods are used to analyze the morphology,element composition,photoelectric performance,photocatalytic ability and stability of the sample.The research results show that the mixing of nitrogen and argon will change the way and degree of plasma etching of the sample,and the doping of the gap N will also inhibit the generation of bulk oxygen vacancies in the sample,so that the photogenerated carriers in the sample can be separated and separated.The transfer speed has been greatly improved.The sample treated with nitrogen/argon plasma for120 min had the best photocatalytic performance,and 82.46% of tetracycline was degraded after 2 h of visible light irradiation.