Preparation Of Supported P-n Heterojunction Photocatalyst Material And Its Performance Study

As the economy continues to develop,people's living standards continue to improve,but along with development,there are many problems that threaten human health,such as water pollution,especially printing and dyeing wastewater,which contains various toxic and harmful substances such as dyes and heavy metal ions.Common adsorption methods and electrochemical methods have disadvantages such as high cost and difficulty in recovery.Therefore,the use of photocatalytic technology with clean and efficient effects to treat pollutants has become a research hotspot.The BiOI semiconductor photocatalyst has a narrow band gap?1.8 eV?and can perform photocatalytic degradation reaction under visible light,but it has problems such as recombination of photo-generated electron-hole pairs and easy aggregation in water.Therefore,for the above two problems,the methods of forming p-n heterojunction and including photocatalytic support can be effectively solved.The main work is as follows:?1?Polystyrene?PS?spheres are prepared by suspension polymerization and used as support for photocatalyst.The BiOI photocatalyst is deposited on the PS spheres by the first hydrothermal reaction,and the Ti0₂ is deposited on the surface of the BiOI by the second hydrothermal reaction to form p-n heterojunction.The PS/BiOI/Ti0₂ composite photocatalyst has a large specific surface area,can absorb insoluble organic pollutants,and can also photo-degrade soluble organic pollutants,and has the dual functions of adsorption-photocatalysis.Further research indicates that the degradation efficiency of the PS/BiOI/Ti0₂ composite photocatalyst to rhodamine B?RhB?aqueous solution reaches 95.8%in 7.5 hours.?2?Polyacrylonitrile?PAN?micro/nano composite fiber can be prepared as support for photocatalyst by wet spinning and electrospinning.BiOI photocatalyst is deposited on the surface of the PAN micro/nano composite fiber by the first hydrothermal reaction,and Bi2WO6 is deposited on the surface of BiOI by the second hydrothermal reaction to form p-n heterojunction.After 7.5 hours of illumination,the degradation of RhB aqueous solution by BiOI/Bi2WO6 powder is 67.3%,while that of PAN/BiOI/Bi₂W0₆ micro/nano composite fiber reaches 91.1%,due to the synergistic effect of photocatalyst and support.