Preparation And Properties Of Bi₂WO₆/Bi₂O₂CO₃ Photocatalyst Based On Heterojunction

With the rapid development of the medical industry and the printing and dyeing industry,a large number of antibiotic wastewater and dye wastewater are produced,which seriously threaten the health of human beings and the safety of the ecosystem.Compared with the traditional treatment methods,photocatalytic technology based on semiconductors is a green,efficient and economic sewage treatment method.Bi₂WO₆photocatalyst as a rise in recent years,because of easy preparation,non-toxic,strong stability,the advantages of the forbidden band width narrow and wide attention by scholars,but pure Bi₂WO₆due to carrier recombination rate is high,leads to lower its photocatalytic activity,and powdered catalyst into the problems existed in the water body is difficult to recycle.In this paper,the photocatalytic performance of Bi₂WO₆was improved by means of morphology regulation and heterojunction construction,and the recyclability of the catalyst was improved by loading the heterojunction catalyst on the carbon felt,making it more conducive to the application in the actual sewage treatment.The specific research contents and conclusions are as follows.（1）Taking Bi（NO₃）₃·5H₂O and Na₂WO₄·2H₂O as precursors,Bi₂WO₆with various morphologies was obtained by adjusting the p H value of the precursor solution.Taking Rh B and CIP as the research objects,the influence of p H value of precursor solution on the catalytic activity of the catalyst was investigated.The photocatalytic activity of the catalyst from high to low was p H=3,p H=7,p H=5,p H=9.（2）Bi₂WO₆/Bi₂O₂CO₃heterojunction photocatalyst was prepared by one-step solvothermal method.The effect of Bi₂WO₆/Bi₂O₂CO₃composite ratio on its photocatalytic performance was studied.The photocatalytic activity increased first and then decreased with the increase of Bi₂WO₆content.The photocatalytic activity of BOCW3 was the highest,and the degradation rate of CIP and Rh B was 98.2%and95.3%,respectively.This is because the unique three-dimensional structure of the composite and the tightly connected heterojunction interface accelerate the charge transfer and improve the electron-hole lifetime.The photocatalytic mechanism of Bi₂WO₆/Bi₂O₂CO₃heterojunctions was investigated.The active species that played a major role in photocatalytic degradation were superoxide radical(·O_2-)and hole（h⁺）.（3）Bi₂WO₆/Bi₂O₂CO₃heterostructure was loaded onto carbon blanket,and the photocatalytic activity of the catalyst was investigated by visible light degradation of CIP and Rh B,and the effects of catalyst loading,initial p H value and matrix salt ions in solution on the photocatalytic activity of the catalyst were studied.The results showed that the optimal loading of Bi₂WO₆/Bi₂O₂CO₃was 0.15 g,the initial p H value of solution and the matrix salt ions in solution had no effect on the degradation of CIP.The cyclic degradation experiments showed that the catalyst had good stability.