The Preparation And Antibacterial Properties Of Bismuth Composite Photocatalytic Materials

With the economic development of modern society,the pursuit of a safe and healthy living environment has become a common goal of mankind.In recent years,the problem of microbial contamination in the environment has become a serious challenge to the world.Therefore,there is an urgent need to find new types of antibacterial materials.Inorganic photocatalytic antibacterial materials have become a research hotspot due to their high activity,good thermal stability,small toxic side effects and low price.In this paper,bismuth-based photocatalytic materials bismuth oxide（Bi₂O₃）,bismuth oxyhalide（BiOX）and carbon quantum dots（CQDs）are used as raw materials,β-Bi₂O₃@BiOBr,β-Bi₂O₃@BiOI and CQDs/β-Bi₂O₃@BiOI composites were prepared.The aim is to improve the separation efficiency of photogenerated carriers,broaden the absorption range of visible light and enhance the photocatalytic activity of the composites.The composition,morphology,structure,photoelectric properties and photocatalytic antibacterial properties were analyzed and discussed,and the photocatalytic antibacterial mechanism was clarified by capture experiments.The specific research contents of this paper are as follows:（1）The core-shellβ-Bi₂O₃@BiOBr photocatalyst was successfully designed by a facile ultrasonication method.The structures and properties of the composites were characterized by XRD,TEM,SEM,HRTEM and XPS.The results showed that theβ-Bi₂O₃@BiOBr composites were successfully prepared.PT and EIS results showed that the e^--h⁺pairs can be effectively separate inβ-Bi₂O₃@BiOBr composites.The photocatalytic antibacterial experiment was tested under LED light,the results showed thatβ-Bi₂O₃@BiOBr composites could completely inactivate E.coli within40 min,and completely inactivate S.aureus within 50 min,the as-synthesizedβ-Bi₂O₃@BiOBr displayed better photocatalytic antibacterial activity than pureβ-Bi₂O₃ and BiOBr.SEM results show that the structure and morphology of E.coli are gradually destroyed by photocatalyst,LSCM further showed that more and more E.coli was inactivated as the light time prolonged.According to the results of the active species capture experiment and the band structure,the photocatalytic antibacterial mechanism ofβ-Bi₂O₃@BiOBr was clarified,·OH,e^-,and h⁺were all active species,of which h⁺played a major role in the antibacterial process.（2）The core-shellβ-Bi₂O₃@BiOI photocatalyst was successfully designed by a facile ultrasonication method.The structures and properties of the composites were characterized by XRD,TEM,SEM,HRTEM and XPS.The results showed that theβ-Bi₂O₃@BiOI composites were successfully prepared.PT and EIS results showed that the e^--h⁺pairs can be effectively separate inβ-Bi₂O₃@BiOI composites.The photocatalytic antibacterial experiment was tested under LED light,the results showed thatβ-Bi₂O₃@BiOI composites could completely inactivate E.coli within 30min,and completely inactivate S.aureus within 40 min,the as-synthesizedβ-Bi₂O₃@BiOI displayed better photocatalytic antibacterial activity than pureβ-Bi₂O₃and BiOI.SEM results show that the structure and morphology of E.coli are gradually destroyed by photocatalyst,LSCM further showed that more and more E.coli was inactivated as the light time prolonged.According to the results of the active species capture experiment and the band structure,the photocatalytic antibacterial mechanism ofβ-Bi₂O₃@BiOI was clarified,·OH,e^-,and h⁺were all active species,of which h⁺played a major role in the antibacterial process.（3）The core-shell CQDs/β-Bi₂O₃@BiOI photocatalyst was successfully designed by a facile ultrasonication method.The structures and properties of the composites were characterized by XRD,TEM,SEM,HRTEM and XPS.The results showed that the CQDs/β-Bi₂O₃@BiOI composites were successfully prepared.The DRS results indicated that the introduction of CQDs can enhance the material’s absorption of visible light.PT and EIS results showed that the e^--h⁺pairs can be effectively separate in CQDs/β-Bi₂O₃@BiOI composites.The photocatalytic antibacterial experiment was tested under LED light,the results showed that CQDs/β-Bi₂O₃@BiOI composites could completely inactivate E.coli within 20 min,and completely inactivate S.aureus within 40 min,the as-synthesized CQDs/β-Bi₂O₃@BiOI displayed better photocatalytic antibacterial activity than pureβ-Bi₂O₃,BiOI and 17.5%β-Bi₂O₃@BiOI.SEM results show that the structure and morphology of E.coli are gradually destroyed by photocatalyst,LSCM further showed that more and more E.coli was inactivated as the light time prolonged.According to the results of the active species capture experiment and the band structure,the photocatalytic antibacterial mechanism of CQDs/β-Bi₂O₃@BiOI was clarified,·OH,e^-,and h⁺were all active species,of which h⁺played a major role in the antibacterial process.