Preparation And Photocatalytic Performance Of TiO₂ Nanotube-based Composites

Because of the continuous progress of industry,the problem of environmental contamination becomes more and more serious.Among them,water pollution does great harm to human fitness and economic development of society.Therefore,it is urgent to find a low-cost,no secondary pollution and efficient water pollution treatment means.Semiconductor photocatalysis technology is favored by researchers because of its low manufacturing cost,safe and pollution-free raw materials and high pollutant removal efficiency.As a semiconductor photocatalyst,the properties of stable state and inexpensive price make TiO₂ be used widely.However,the band gap up to 3.2 e V greatly limits its utilization efficiency for visible light and infrared light,and the high electron-hole pair recombination rate also reduces its activity of photocatalysis.In this work,anatase phase TiO₂ nanotubes with well-distributed morphology were prepared by electrostatic spinning technology,and the TiO₂ nanotubes were further supported with narrow band gap semiconductor materials to form heterojunction,which reduced the band gap and enhanced the electron-hole pair separation ability,effectively improved the photocatalytic activity and further provided good adsorption performance.The main research results are as follows:（1）By using sacrificial template technology,anatase phase TiO₂ nanotubes were produced,and Cu₉S₅ layer was further supported on TiO₂ nanotubes by hydrothermal method.Through experiments and theoretical calculations,it is proved that TiO₂/Cu₉S₅heterostructure has a good separation ability for electron-hole pairs.The photocatalytic degradation experiment showed that TiO₂/Cu₉S₅ heterostructure photocatalyst could achieve 98%removal rate of organic dye Rhodamine B within 120 min.The removal rate of tetracycline hydrochloride can reach 99%within 120 min.At the same time,the photocatalysis TiO₂/Cu₉S₅ exhibited satisfactory cyclic degradation ability.（2）Anatase phase TiO₂ nanotubes were prepared by sacrificial template method,and Bi₂O₃/Bi₂O_2.33 nanosheets were supported on TiO₂ nanotubes by hydrothermal method.Theoretical calculation proves that,compared with pure anatase phase TiO₂,the composite photocatalyst can significantly reduce the band gap width.Meanwhile,theoretical calculation and experiment prove that TiO₂/(Bi₂O₃/Bi₂O_2.33)heterojunction has a good separation ability for electron-hole pairs.The adsorption experiments show that the composite photocatalysis can reach 70%adsorption rate for high concentration organic dye methyl orange in 60 min.The photocatalytic degradation experiment showed that the removal rate of organic dye Rhodamine B composite photocatalyst could reach93%within 60 min,and that of high concentration antibiotic tetracycline hydrochloride could reach 96%within 120 min.At the same time,composite photocatalysis showed good cyclic degradation ability for organic pollutants.