Research On The Photocatalytic Performance Of Carbon/Nitrogen Modified Titanium Dioxide Nanotubes

Semiconductor materials are key factors in photocatalytic reactions.Among many photocatalyst candidates,such as cadmium sulfide?CdS?,cadmium selenide?CdSe?,indium phosphide?InP?,titanium dioxide?TiO₂?,tungsten trioxide?WO₃?,silver oxide?Ag₂O?,silver sulfide?Ag₂S?,cuprous oxide?Cu₂O?,bismuth molybdate?Bi₂MoO₆?and bismuth tungstate?Bi₂WO₆?,etc.,among these semiconductors,TiO₂ is an early and relatively good photocatalyst.It has high photoactivity in the ultraviolet?UV?region.In order to better explore the application of TiO₂ in photocatalytic degradation of pollutants,people have continuously explored ways to reduce the band gap of TiO₂ to improve light absorption?energy band regulation?and increase its quantum yield?charge space separation?.In this paper,a simple and efficient hydrothermal synthesis method was selected,and the nano-TiO₂ tubular material was mainly studied.Its unique one-dimensional structure,large surface area and strong adsorption capacity can improve the electron transport efficiency and photocatalytic performance of TiO₂.According to the relationship between structure and performance,high-efficiency photocatalytic materials are obtained by doping design and functional compounding of nano-TiO₂ tubular materials.In the first part,TiO₂ was prepared by sol-gel method and hydrothermal synthesis of TiO₂nanotubes,and nitrogen was doped with urea as nitrogen source.The crystal forms,morphology,optical properties and photocatalytic activity of TiO₂,TiO₂ nanotubes,nitrogen-doped TiO₂ and nitrogen-doped TiO₂ nanotubes at different calcination temperatures were investigated by various characterization methods.When the optimum calcination temperature of the catalyst is400°C,the morphology of the TiO₂ nanotubes is relatively complete,the tube shape is uniform and uniform,and the band gap is reduced after nitrogen-doped TiO₂?UV-vis spectrum?,and the TiO₂ pair is broadened.The absorption range of light.Rhodamine B was used as a simulated pollutant.After 5h of visible light irradiation,the TiO₂ raw material had almost no photocatalytic activity,while the nitrogen-doped TiO₂ nanotubes were exposed to visible light for 5h,and the degradation rate was close to 76%,which was higher than the degradation rate of TiO₂ raw materials.The degradation rate of nitrogen-doped TiO₂ was 59%.The second part explores the photocatalytic performance of TiO₂/graphene and graphene/TiO₂ nanotube composites.In particular,the effects of different ratios of graphene on the photocatalytic effect of graphene/TiO₂ nanotube composites were considered.Combined with the high conductivity of graphene and the properties of composite semiconductors,the high-efficiency photocatalytic performance of the composites was explained reasonably,and the photocatalytic reaction mechanism was discussed.Rhodamine B was used as a simulated pollutant.After 1.5h of light irradiation,TiO₂ nanotubes only degraded by 24%,3:100 degraded by 57%,5:100 had a degradation rate of 73%,and 10:100 degraded by 38%.Among them,5:100 has the highest photodegradation rate and exhibits excellent photocatalytic performance.In summary,nitrogen-doped TiO₂ nanotubes have good visible light photocatalytic activity and broaden to the visible region.Graphene/TiO₂ nanotubes better solve the problem of carrier separation.According to the relationship between structure and performance,the photocatalytic performance of nanotubes is improved by doping design and functional compounding,which is of great significance in environmental management.