Research On The Controllable Preparation Of WO₃ Composite Materials And Its Photocatalytic Production Of Hypochlorous Acid For Antifouling Performance

With the development of the marine economy,marine biofouling is an extensive problem,causing economic loss and environmental problems.Therefore,there is still an urgent need to develop an efficient and environmentally friendly material to resist marine antifouling.In this paper,based on the good photocatalytic activity and environment friendly property of tungsten trioxide（WO₃）semiconductors,it is used for photocatalytic production of hypochloric acid（HClO）for antifouling.WO₃semiconductor materials have controllable synthesized by hydrothermal technology.With the help of metal cocatalysts and the construction of the heterojunction structures,which promote the efficiency of photo-generated electron-hole pair separation,and then enhance the performance of photocatalytic sterilization and algae removal by WO₃ photocatalytic production of HClO.The mechanism of the photocatalytic reaction was clarified.The study contents are as follows:First,WO₃ semiconductor materials with different morphologies were synthesized by hydrothermal method,nano-Pt was loaded on the surface of WO₃ by noble metal doping method to construct Pt/WO₃ photocatalyst.The performance of Pt/WO₃ with different morphologies under visible light photocatalytic production of HClO was compared in 0.5M Na Cl solution.Among them,1 wt%Pt/WO₃ hollow microspheres photocatalyzed 2 h to produce 14.52μM HClO,which was 7 times that of other other morphologies.Through the degradation experiment of Rhodamine B solution（Rh B）and the sterilization and algae removal experiment under visible light irradiation,it was found that its visible light irradiation for 4 h,3 h and 8 h could degrade Rh B and kill bacteria and algae.Furthermore,based on the electron spin resonance（ESR）test and its band structure,it is elucidated that Cl^-is oxidized at the valence band position of WO₃ to generate HClO,and the nano-Pt surface reduces O₂ to generate H₂O₂.Second,Through the design of magnetic core@shell and core@double-shell structures,Fe₃O₄@WO₃ and Fe₃O₄@Si O₂@WO₃semiconductor materials were pre-pared and doped with nano-Pt.The performance of Pt/Fe₃O₄@WO₃and Pt/Fe₃O₄@Si O₂@WO₃photocata-lysts under visible light photocatalytic production of HClO was compared in 0.5 M Na Cl solution,Only Pt/Fe₃O₄@Si O₂@WO₃ photocatalyzed 2 h to produce 6.31μM HClO.The magnetic recovery performance of WO₃ and the photocatalytic sterilization and algae removal experiment were verified under applied magnetic field indicated the stability and long-time reusability.The mechanism of its photocatalytic production of HClO is consistent with that of Pt/WO₃ photocatalyst.Third,Considering the economic costs of the Pt cocatalyst,the semiconductor composite is used to replace the precious metal cocatalyst.Z-scheme WO₃/Cd S hetero-junction was prepared by a combination of hydrothermal method and precipi-tation method.The performance of WO₃/Cd S and Pt/WO₃photocatalysts under visible light photocatalytic production of HClO was compared in 0.5 M Na Cl solution.The WO₃/Cd S photocatalysis can produce 3.54 mg/L chlorine for 2 h,which is three times that of the 1 wt%Pt/WO₃sample.Through the sterilization and algae removal experiments under visible light irradiation,it was found that the visible light irradiation for 3 h and 12 h could kill bacteria and algae.In addition,based on the ESR test of WO₃/Cd S and its band structure,it is clarified that Cl^-is oxidized at the valence band position of WO₃ to generate HClO,and the conduction band position of Cd S reduces O₂ to generate H₂O₂.