Preparation And Photocatalytic Performance Of Bi_xO_yCL_z/BiOI Composite Material

The development of industry not only promotes economic improvement,but also brings about environmental problems.Seeking suitable technology to reduce environmental pollution is a major challenge facing us at present.Photocatalytic technology using solar energy as the light source,has the advantages of green,environmental protection,high efficiency,showing a unique advantage in environmental governance.Bismuth photocatalytic materials have been widely used in the field of photocatalysis due to their unique layered structure,suitable band gap and high stability.In this paper,Bi₃O₄Cl/Bi OI,Bi₁₂O₁₅Cl₆/Bi OI and CQDs/Bi₁₂O₁₅Cl₆/Bi OI composites were prepared by combining Bi OI（p-type semiconductor）with Bi_xO_yCl_z（n-type semiconductor）and CQDs,respectively.Effectively promote the separation of charge in the monomer catalyst,achieve the effect of degrading pollutants and inactivating bacteria.The specific research contents of this paper are as follows:（1）Bi₃O₄Cl was synthesized by hydrothermal method followed by calcination,Bi OI and Bi₃O₄Cl/Bi OI（Cl/Bi OI）composites were synthesized by ultrasonic method.The composition,morphology and structural characteristics of the material were analyzed by XRD,TEM,HRTEM and XPS characterization,indicating that the Bi₃O₄Cl/Bi OI composite was successfully prepared.Photocurrent and EIS characterization showed that the separation efficiency of e^-and h⁺in the composite material was significantly improved.The photodegradation（MO,TC）and antibacterial（E.coli）experiments under LED light showed that the photocatalytic performance of the composite was apparently higher than a single material.The best sample Cl/Bi OI-30%could degrade 85.5%MO in 90 minutes,73.5%TC in 180minutes,and inactivated 100%E.coli in 40 minutes.Finally,the photocatalytic mechanism was determined by combining the active species capture experiment,Mott-Schottky curve and band energy structure analysis.（2）Bi₁₂O₁₅Cl₆ was synthesized by hydrothermal method followed calcination method,Bi OI and Bi₁₂O₁₅Cl₆/Bi OI（Cl₆/Bi OI）composite with core-shell structure was synthesized by stirring method.The composition,morphology and structural characteristics of the material were analyzed by XRD,SEM,TEM,HRTEM and XPS characterization.Photocurrent and EIS characterization showed that the separation efficiency of e^-and h⁺in the composite material was significantly improved.The photodegradation（MO,TC）and antibacterial（E.coli）experiments under LED light showed that the photocatalytic performance of the composite was apparently higher than a single material.The best sample Cl₆/Bi OI-3 could degrade 90.3%MO in 90minutes,75.5%TC in 180 minutes,and inactivated 100%E.coli in 40 minutes.Finally,the photocatalytic mechanism was determined by combining the active species capture experiment,Mott-Schottky curve and band energy structure analysis.（3）By introducing CQDs into the previous system,CQDs/Bi₁₂O₁₅Cl₆/Bi OI（CQDs/Cl₆/Bi OI）composites were synthesized.XRD,TEM,HRTEM and XPS tests showed that the CQDs/Bi₁₂O₁₅Cl₆/Bi OI ternary photocatalyst was successfully synthesized.DRS characterization showed that the introduction of CQDs could enhance the visible light absorption intensity of the material,and the photocurrent and EIS characterization showed that the separation efficiency of e^-and h⁺in the ternary compounds was much higher than binary compounds and a sigle material.The photodegradation（MO,TC）and antibacterial（E.coli）experiments under LED light show that the photocatalytic performance of composite materials was better than that of monomer and binary composite.The best sample 1%CQDs/Cl₆/Bi OI could degrade 95.8%MO in 90 minutes,79.9%TC in 150 minutes,and inactivated 100%E.coli in 30 minutes.Finally,the photocatalytic mechanism was determined by combining the active species capture experiment,Mott-Schottky curve and band energy structure analysis.