Composite Modification And Photocatalytic Activity Study Of Bismuth Bromide

Since the poor photocatalytic performance of monomer bismuth bromide limits its practical application,it is necessary to improve the photocatalytic performance of bismuth bromide by modification.I have found that bismuth bromide can improve photocatalytic performance through heterostructure formation and recombination,so this paper has conducted in-depth research in this regard.It has been mentioned in many literatures that the formation of binary heterostructures can improve the photocatalytic activity of bismuth bromide.Therefore,a ternary heterostructure bismuth bromide with higher photocatalytic properties is conceived and prepared.And the composite of carbon quantum dots and bismuth bromide was realized.The specific content of this paper is as follows:1.A stepwise solvothermal method is used to combine graphite phase carbon nitride?g-C₃N₄?and silver bromide into bismuth bromide to obtain a ternary heterostructure bismuth bromide microspheres.The composition,morphology and optical properties of the samples were characterized by XRD,SEM,EDS,XPS,UV-vis and other inspection methods.In the prepared sample,a uniform stack of graphite phase carbon nitride and silver bromide was laminated on the surface of the bismuth bromide microspheres.Compared with pure bismuth bromide,the ternary heterostructure bismuth bromide has narrowed the forbidden band width,effectively increasing the generation rate of photogenerated carriers,and significantly expanding the absorption range of the visible spectrum.In the heterostructure,electrons migrate to the conduction band of bismuth bromide,and the holes accumulate in the valence band of graphite phase carbon nitride.The separation of electron holes in space effectively suppresses the recombination of electron hole pairs.Finally,we used the visible light irradiation sample to degrade rhodamine B in liquid phase to analyze the photocatalytic activity of the sample.After 60min illumination,the efficiency of the monomer bismuth bromide degrading rhodamine B was 32.3%,and the two binary heterostructure samples were The degradation rates were 52%and 69%,respectively,while the degradation rate of the ternary heterostructure samples was 90.5%.2.Using a one-step hydrothermal method,the carbon quantum dots were compounded into BiOBr:Yb³⁺,Er³⁺,and the bismuth bromide nanosheets after composite modification were obtained.The photocatalytic activity test showed that the degradation efficiency of pure bismuth bromide was 46.7%after 50 min illumination,and the degradation rate of modified bismuth bromide reached 94.4%.The reasons for the improvement of photocatalytic efficiency of the sample were analyzed by means of XRD,SEM,TEM,PL spectroscopy and nitrogen adsorption desorption.It proved that it has a large specific surface area and smaller electron-hole pair recombination rate.The larger specific surface area can provide more contact sites for the reactants,and smaller electron-hole pair recombination rate can inhibit the recombination of photogenerated carriers,thereby improving the photocatalytic performance of the material.