Preparation And Photocatalytic Performance Of Indium Polysulfide Composite Semiconductor Photocatalyst

With the rise of photocatalytic technology,more and more people are focusing on the use of photocatalytic technology to solve the problems of environmental pollution and energy shortage caused by industrial development.Among them,the treatment of water pollution by using photocatalysts has attracted particular attention.In recent years,researches on the photodegradation of organic pollutants using metal oxides and sulfides as photocatalysts have attracted huge attention attention at home and abroad.Polysulfide of In is a semiconductor photocatalytic material with excellent properties and widely studied,such as ZnIn₂S₄,In₂S₃.They all have a narrow bandgap and can absorb in the near-infrared region.However,their stability is poor,so photo corrosion is very easy to occur during the photocatalytic reaction.Photo-generated electrons and holes are also easily recombined.This seriously affects their photocatalytic properties.Recombinating with other semiconductor materials is a method for effectively improving photocatalytic activity.Based on this,the WO₃/ZnIn₂S₄,V₂O₅/In₂S₃ and V₂O₅/In₂S₃/RGO composite photocatalytic materials were prepared by a simple solvothermal method,which inhibited the recombination of photo-generated electrons and holes and improved the photocatalytic activity and stability of ZnIn₂S₄ and In₂S₃.The main research contents are as follows:（1）WO₃/Zn In₂S₄ composite photocatalyst were successfully prepared by hydrothermal method.The results showed that WO₃ particles were uniformly distributed on the surface of Zn In₂S₄microspheres and formed a heterojunction structure.Methyl orange（MO）was selected as simulated contaminant to investigate the photocatalytic activity.It was found that the photocatalytic activity of WO₃/ZnIn₂S₄ was better than that of pure Zn In₂S₄,indicating that the introduction of WO₃ improved the photocatalytic activity of ZnIn₂S₄.When the molar ratio of WO₃ to ZnIn₂S₄ is 1:4,the material has the best photocatalytic activity.Under visible light irradiation,98.9%of MO can be degraded in 80 minutes.The result activity factor capture experiment showed that the active factor of WO₃/Zn In₂S₄ in photodegradation of MO is hole（h⁺）.（2）One-dimensional（1D）V₂O₅ semiconductor were prepared by hydrothermal-calcination method,and then a novel flower-like V₂O₅/In₂S₃ composite photocatalyst was constructed by hydrothermal method.The photocatalytic degradation of MO showed that the photocatalytic activity of V₂O₅/In₂S₃ is much higher than that of In₂S₃ monomer,which indicates that the introduction of V₂O₅ improves the photocatalytic activity of In₂S₃.When the mass fraction of V₂O₅ is 5%,its photocatalytic activity is the highest and 88.2%MO can be degraded by visible light irradiation for 120 minutes.The activity factor capture experiment showed that the active factors in the process of photodegradation of MO were superoxide radical（·O₂^-）and hole（h⁺）.（3）V₂O₅/In₂S₃/RGO composites were prepared by hydrothermal method.The influence of the doping amount of graphene on the photocatalytic activity was studied in detail.The photodegradation experiments of MO were then carried out.The results showed that compared with V₂O₅/In₂S₃,the photocatalytic activity of V₂O₅/In₂S₃/RGO was improved,and there was an optimal value for the doping amount of graphene.When the mass fraction was 4%,the photocatalytic performance was the best.After 120min irradiation,the degradation rate of MO reached 93.3%.The activity factor capture experiment results showed that the active factors of V₂O₅/In₂S₃/RGO were superoxide radical superoxide radical（·O₂^-）and hole（h⁺）,consistent with the active factor of V₂O₅/In₂S₃.