Study On Preparation And Photocatalytic Performance Of Tungsten Selenide Composites

Photocatalysis technology is a green new technology to solve environmental and energy problems.It is currently widely used in the fields of degradation of pollutants,hydrogen production by hydrolysis and CO₂ reduction.Tungsten diselenide（WSe₂）material in the transition metal chalcogenide compound has a wide light response range,good thermal stability and chemical properties,and can be used as a photocatalytic material.In this paper,WSe₂ is compounded with other photocatalytic materials:bismuth oxide（Bi₂O₃）,indium vanadate（In VO₄）and silver phosphate（Ag₃PO₄）to prepare a composite material to improve the photocatalytic performance of the material under visible light conditions.The main research contents and conclusions of this article are as follows:（1）Nano-WSe₂,Bi₂O₃ and WSe₂/Bi₂O₃ composite materials were successfully prepared by one-step solvothermal method,WSe₂ was flower-shaped and Bi₂O₃ was rod-shaped.The photocatalytic performance of WSe₂/Bi₂O₃ composite is significantly higher than that of Bi₂O₃,and the photocatalytic performance of WSe₂/Bi₂O₃composite with WSe₂ mass fraction of 20%is the strongest.Under natural light conditions,the removal rate of methylene blue（MB）reaches 98.4%,which is 2.54times the removal rate of Bi₂O₃ nanorods under the same conditions.The degradation rate of the composite material is 10 times that of Bi₂O₃.WSe₂/Bi₂O₃ has good cycle stability.After 6 cycles of experiments,its MB degradation rate still reached 94.1%.Active group capture experiments show that in this reaction system,holes（h⁺）play a major role in the degradation of pollutants,followed by·O₂^-,and·OH also has a certain contribution.（2）Preparation of In VO₄ nano flower ball and WSe₂/In VO₄ composite material by hydrothermal method.The results of the photocatalysis experiments showed that the WSe₂/In VO₄ composite with a WSe₂ mass fraction of 10%had the highest MB degradation rate,reaching 98.8%,which was 2.89 times that of In VO₄ nanospheres,and the WSe₂/In VO₄ composite degradation rate was 11 times that of In VO₄,Indicating that the photocatalytic performance of WSe₂/In VO₄ composites has been significantly improved.WSe₂/In VO₄ has good cycle stability.After 6 cycles of experiment,its MB degradation rate is still 93.6%.Active group capture experiments show that in this reaction system,O₂^-plays a major role,followed by h⁺,and·OH also participates in the reaction.（3）Prepare Ag₃PO₄ and WSe₂/Ag₃PO₄ composite materials by in-situ deposition.The results of photocatalysis experiments show that the photocatalytic performance of WSe₂/Ag₃PO₄ composite material is significantly enhanced compared with Ag₃PO₄.Among them,WSe₂/Ag₃PO₄ with a WSe₂ mass fraction of 6.5%has the highest MB degradation rate,reaching 98.5%,which is 1.99 times that of Ag₃PO₄.Its degradation rate is 5.91 times that of Ag₃PO₄.After 6 cycles of experiments,the WSe₂/Ag₃PO₄composite still has a degradation rate of 92.1%for MB.Active group capture experiments show that in this reaction system,h⁺plays a major role,and·O2^-followed by·OH also has a certain contribution.The composite material prepared by WSe₂ and other photocatalytic materials has a wider light response range and can more effectively use visible light;the formation of type-II type heterojunction can effectively separate the transition photogenerated electrons and suppress the photogenerated electrons-holes.Compounding significantly improves the photocatalytic performance of composite materials.