Preparation And Properties Of Vanadium-Based Nanocomposite Photocatalysts

As a new type of technology,photocatalytic technology is one of the effective strategies to alleviate the greenhouse effect,solve the energy crisis,and manage the environment.The key to photocatalysis is the development of novel and efficient semiconductor photocatalysts.Vanadates have attracted much attention due to their good visible light response and narrow band gap.However,the single vanadate semiconductor material has low efficiency of separation and transfer of photogenerated carriers and high recombination rate,which limits its practical application in the field of photocatalysis.In order to improve the photocatalytic activity of vanadate semiconductors,the method of compounding semiconductors and loading metal nanoparticles was used to enhance them.The specific research can be listed as follows.（1）The Bi VO₄ octahedron was obtained by hydrothermal reaction.After that,Bi VO₄ was further hydrothermally treated with hydrazine hydrate as reducing agent to prepare Bi/Bi VO₄ binary composites.Then,using zinc chloride,indium trichloride and thioacetamide（TAA）as raw materials,Zn In₂S₄ nanoparticles were grown on the surface of Bi/Bi VO₄by a solvothermal method to construct a ternary composite structure of Zn In₂S₄/Bi/Bi VO₄.The loading of Zn In₂S₄ was regulated by adjusting the amounts of the raw materials.The photocatalytic CO₂ reduction test was performed using a 300 W xenon lamp with an optical filter（λ>420 nm）as the light source.The results showed that the Zn In₂S₄/Bi/Bi VO₄ had strong photocatalytic performance,and the CO generation rate was 5.46μmol·g^–1·h^-1,which is 10 times that of Zn In₂S₄.（2）The Bi VO₄ microplates were synthesized by a similar method,and The Bi/Bi VO₄ was prepared by using hydrazine hydrate as reducing agent.The Ti₃C₂ nanosheets were prepared by selectively removing the Al layer in Ti₃Al C₂.Then,The Ti₃C₂/Bi/Bi VO₄ ternary composites were prepared by electrostatic self-assembly.The photocatalytic degradation test was carried out with a 500 W xenon lamp as the light source.The results showed that the Ti₃C₂/Bi/Bi VO₄ had enhanced photocatalytic activity,and the degradation efficiency of Rhodamine B achieved 95%,which was significantly better than that of Bi VO₄（45%）.（3）The Ag_0.4V₂O₅ nanorods were synthesized by hydrothermal method,and then Bi₂S₃ nanoparticles were loaded on the surface of Ag_0.4V₂O₅ nanorods with Bi（NO₃）₃·5H₂O and TAA as raw materials to form the Bi₂S₃/Ag_0.4V₂O₅ composite structure.The loading of Bi₂S₃ was regulated by adjusting the amount of Bi（NO₃）₃·5H₂O and TAA.The photocatalytic CO₂ reduction test test shows that the photocatalytic activity of the Bi₂S₃/Ag_0.4V₂O₅ composite is significantly improved compared with the single-component semiconductor Bi₂S₃.The enhanced photocatalytic activity can be attributed to the formation of Z-scheme heterojunction,which improves the separation efficiency of photogenerated carriers.