Preparation And Antibacterial Properties Of Photocatalytic Materials Based On Tungsten Trioxide/Carbon Nitride/Bismuth Compound

Infectious diseases caused by bacteria are spreading rapidly all over the world,which is also a serious public health challenge in the world.In addition,bacteria are prone to drug resistance due to heavy use of antibiotics,which makes it hard to treat infectious diseases,and even leads to various complications,posing a great threat to life.Therefore,how to effectively eliminate bacteria and avoid the occurrence of bacterial resistance has become an important research topic in the field of antibacterial.Photocatalytic antibacterial technology has become one of the hotspots of current antibacterial research due to its advantages of green,pollution-free,high cost performance,good bacterial inactivation effect,and no bacterial resistance.For purpose of enhancing the photocatalytic activity of WO₃/g-C₃N₄,bismuth-based compounds（Bi OBr,BiOI and Bi₄O₅I₂）were respectively compounded with it to obtain WO₃/g-C₃N₄/Bi OBr,WO₃/g-C₃N₄/BiOI and WO₃/g-C₃N₄/Bi₄O₅I₂ new ternary photocatalysts.The formation of ternary heterojunction accelerated the separation and migration of photogenerated carriers,improved the photocatalytic performance,and achieved an excellent antibacterial effect.The main research contents of this paper are as follows:（1）WO₃/g-C₃N₄ was synthesized by a two-step calcination method,and then a new ternary photocatalyst WO₃/g-C₃N₄/Bi OBr was synthesized in situ at room temperature.Characterizations such as XRD,FT-IR,XPS and TEM prove that WO₃/g-C₃N₄/Bi OBr had been successfully prepared,and there was a tight heterogeneous structure among the components.Photocurrent and electrochemical impedance analysis showed that compared with WO₃/g-C₃N₄ and Bi OBr,the ternary material WO₃/g-C₃N₄/Bi OBr had a higher separation efficiency of photogenerated carriers.The results of antibacterial experiments showed that 39%WO₃/g-C₃N₄/Bi OBr could inactivate E.coli in 20 min and S.aureus in 30 min.Combined with the energy band position and the results of trapping experiments,it was revealed that the photocatalytic antibacterial of the ternary material conforms to the doubleⅡ-scheme mechanism.（2）On the basis of WO₃/g-C₃N₄,a new ternary material of WO₃/g-C₃N₄/BiOI was obtained by in-situ deposition.WO₃/g-C₃N₄/BiOI was synthesized by WO₃,g-C₃N₄ and BiOI by various characterization methods.According to the characterization of photocurrent and electrochemical impedance,WO₃/g-C₃N₄/BiOI ternary material achieved better separation of photogenerated electrons and holes.Antibacterial experiments showed that 26%WO₃/g-C₃N₄/BiOI had the best antibacterial effect,which could inactivate E.coli in 12 min and S.aureus in 20 min.According to the energy band positions and the results of antibacterial capture,the discussion confirmed that the photocatalytic antibacterial mechanism of the ternary material followed the doubleⅡ-scheme.（3）WO₃/g-C₃N₄/BiOI was thermally treated to successfully prepare WO₃/g-C₃N₄/Bi₄O₅I₂ ternary photocatalyst.The structure,composition and morphology of WO₃/g-C₃N₄/Bi₄O₅I₂ were analyzed by a series of characterization methods.The results of photocurrent and electrochemical impedance proved that the photogenerated carriers in WO₃/g-C₃N₄/Bi₄O₅I₂ ternary material could be better separated and migrated.The antibacterial results showed that the ternary material 30%WO₃/g-C₃N₄/Bi₄O₅I₂ had the best performance,which could kill bacteria in 8 min,16 min and 16 min respectively.According to the analysis of energy band position and capture experiment results,WO₃/g-C₃N₄/Bi₄O₅I₂ ternary material conformed to the double II-scheme antibacterial mechanism.