Preparation And Application Of Doped TiO 2 Floating Visible Light Photocatalyst

As a highly efficient solar photocatalyst,the problem of light trapping and recycling of powdered TiO₂ photocatalyst in the liquid phase has severely limited its practical application in the field of photocatalysis.Floating visible light photocatalysts are being promoted as substitutes for powdered TiO₂ photocatalysts.Therefore,the two different types of carriers with different morphologies by different methods have been prepared,and they have been used to treat highly toxic and highly polluted water,meanwhile,the promising degradation performance has been obtained.Firstly,TiO₂ hollow spheres were prepared by soft-template self-assembly,The C,N co-doped TiO₂ hollow sphere floating visible light photocatalyst was fabricated by depositing the prepared TiO₂ hollow sphere powder on the surface of polyurethane foam thought the ultrasonic immersion assisting method.The morphologies and surface element and functional group of the prepared samples were characterized by some characterization.When the temperature is a single factor,the best calcination temperature is 550 ^oC,and then the single factor experiments to determine the mass ratio of titanium source to soft template was 1:1.The toxic phenols were selected as the target pollutants to investigate the degradation effect of the prepared hollow carbon-nitrogen-doped floating TiO₂ hollow spheres under different light conditions,pH,initial concentration and catalyst usage.Finally,the cyclic stability and buoyancy of the prepared floating visible light photocatalysts were investigated and the best conditions for degradation were summarized.The experimental results shown that the C,N co-doped floating TiO₂ hollow sphere visible light photocatalysts had a better treatment effect on the highly toxic phenols,and the performance is relatively stable.Secondly,the 3D layered TiO₂ flower powder was prepared by solvothermal method,the C,N co-doped TiO₂ flower floating visible light photocatalysts were fabricated by solvothermal method,which pre-treated biomass carbon and solvent were mixed.The morphologies and surface element and functional group of the prepared samples were characterized by some characteristic methods.When the temperature is a single factor,the best calcination temperature is 550 ^oC,and then the single factor experiments to determine the doping ratio was 1:5.Rhodamine?RhB?were selected as the target pollutants to investigate the degradation effect of the prepared C,N co-doped floating TiO₂ flower under different light conditions,pH,initial concentration and catalyst usage.Finally,the cyclic stability and buoyancy of the prepared floating visible light photocatalysts were investigated and the best conditions for degradation were summarized.The experimental results shown that the C,N co-doped floating TiO₂flower visible light photocatalysts had a better treatment effect on the dye wastewater,and the performance is relatively stable.Finally,the degradation mechanism and degradation kinetics of C,N co-doped with floating TiO₂ hollow sphere visible light photocatalysts and C,N co-doped floating TiO₂ flower visible light photocatalysts system were studied.Holes and hydroxyl radicals were the main active substances in the catalytic system.Doping carbon and nitrogen can effectively enhance the response in the visible region and electron-hole pair separation speed,while lightweight materials can make the powder catalyst floating on the water to improve the utilization of light.