Construction And Photocatalytic Performance Research Of Copper Bismuth Based Heterojunction

Semiconductor photocatalysis technology has a good application prospect in hydrogen production and water purification due to its unique advantages of mild reaction conditions,stable properties,environmental friendly and direct use of sunlight,which is of great significance to global enery development and environmental governance.In this paper,rod-like copper bismuth(CuBi2O4)photocatalyst was prepared by one-step hydrothermal method,and two heterojunction photocatalysts(CuBi2O4/Bi5O7I@rGO and Ag2MoO4/CuBi2O4)were constructed based on CuBi2O4.The composition,morphology and optical properties of as-synthesized photocatalysts were characterized and analyzed by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier transform-infrared(FT-IR),Raman spectroscopy(Raman),scanning electron microscope(SEM),transmission electron microscopy(TEM),surface area and pore(BET)and UV-vis diffuse reflection spectrum(UV-vis DRS).Rhodamine B(RhB),tetracycline hydrochloride(TC-HCl)and ciprofloxacin(CIP)were used as target pollutants to evaluate the photocatalytic activity of as-prepared materials under simulated sunlight.Finally,the possible photocatalytic mechanism was explored through degradation results and characterization analysis.The details are as follows:Firstly,Bi(NO3)3·5H2O and KI were used as raw materials,and ethylene glycol and water were used as solvents to prepare the flower-like Bi5O7I by a simple hydrothermal method.Then,Bi5O7I was dispersed in a mixed solution of Bi(NO3)3·5H2O,Cu(NO3)2·3H2O and NaOH to obtain CuBi2O4/Bi5O7I composites with different mass ratios by hydrothermal method.Then,20%CuBi2O4/Bi5O7I was used as the main body to hydrothermal reduction with graphene,and the ternary CuBi2O4/Bi5O7I@rGO heterojunction photocatalyst was prepared.This Z-scheme heterojunction structure using rGO as a promoter not only provided more reactive sites,but also accelerated the separation of electron-hole pairs,which was beneficial to the improvement of photocatalytic activity.The three pollutants of RhB,TC-HCl and CIP were degraded under visible light.The results showed that the CuBi2O4/Bi5O7I@1.5%rGO sample has the strongest photodegradation effect.In addition,the environmental parameter factor experiment was added,and the results showed that the higher initial pollutant concentration and the addition of certain anions inhibited the photocatalytic activity.Finally,combining characterization analysis and capture experiment explored the potential mechanism of improving photocatalytic activity.Secondly,the rod CuBi2O4 was prepared by one-step hydrothermal method using Bi(NO3)3·5H2O,Cu(NO3)2·3H2O and NaOH as raw materials,then AgNO3 and Na2MoO4·2H2O were dispersed in the above solutions containing CuBi2O4 to prepare Ag2MoO4/CuBi2O4 composite photocatalysts with different molar ratios,During the preparation process,the size of Ag2MoO4 was significantly reduced because the silver ions were preadsorbed on the rod CuBi2O4 and the structure would limit the growth of Ag2MoO4.The degradation of TC-HCl and RhB showed that the photocatalytic performance of Ag2MoO4/CuBi2O4 samples was significantly improved compared with that of pure CuBi2O4 and Ag2MoO4,which may be attributed to the formation of Z-scheme Ag2MoO4/Ag/CuBi2O4 heterostructure by a small amount of metallic silver produced under light.In addition,the capture experiment proved that superoxide radical and hydroxyl radical played a major role in the degradation of pollutants.Based on the photocatalytic degradation of TC-HCl,the possible photocatalytic reaction mechanism was explored.