The Preparation,Characterization Of Modified Titanium Dioxide And Its Photocatalytic Property

Research has intensively investigated titanate nanotubes due to one-dimensional nanostructure,large internal and external surfaces,ion exchangeability,and photocatalytic activity.These advantages lead to various applications such as solar cells,photocatalysis,and electroluminescent devices.However,the TiO2 high band gap between 3.3 eV and 3.87 eV obstructs application.In other words,only UV light,which occupies less than 5%of the solar spectrum,excites TiO2.Therefore,studies have made great attempts to extend the absorption of TiO2 to visible-light sensitization.This research mainly study the codoped TiO2 nanotubes with visible light catalytic activity.Prepared by hydrothermal method and combined with some other auxiliary means to the preparation of the non-metal and metal codoped TiO2 nanotubes catalyst,improve the degradation of pollutants in the visible light catalytic properties.a)Different non-metal co-doped titanium dioxide nanotubes(TiO2NT)were preformed by one-pot hydrothermal synthesis with urea,thiourea and ammonium fluoride as dopant source respectively.The samples were characterized by SEM,TEM,XRD,BET,FT-IR,UV-Vis and DRS.The photo-catalytic activity under visible light was evaluated by photocatalytic degradation of methyl orange.The adsorption performance of catalyst to methyl orange was studied,and the relationship between nitrogen doping behavior and visible light photo-catalytic property was investigated by the experiment of degradation of methyl orange waste water.The results showed that nanotubular titania prepar-ed by hydrothermal processing using different non-metal elements as dopant in the strong alkaline solution had larger surface area(193.93 m2/g)and lo?wer band gap energy(2.76 eV)than that of TiO2,and nonmetal-doping can activate its visible-light activity.Photo-catalytic degradation of methyl orange tests showed that the thiourea doped titania nanotubes(N,S-TiO2NT)under the visible light had the best degradation rate,methyl orange degraded by 81.5%with illumination of 90 min.The reaction followed a first-order kinetics equation.b)N,Cr-codoped TiO2 nanotubes with larger specific surface area and lower band gap energy compared with undoped TiO2 nanotubes were prepared using hydrothermal methods in a concentrated NaOH solution followed by impregnation.The obtained catalysts were characterized by TEM,XRD,BET,FT-IR,and UV-Vis DRS.The effects of diferent Cr doping amount on the morphology,structure properties,adsorption and photocatalytic activity of N,Cr codoped TiO2 nanotubes were investigated.The photocatalytic activity was evaluated by degradation of methyl orange(MO)under visible light for 100min.The optimum Cr doping at Ti:N:Cr=1:1:10%showed the highest photocatalytic activity,the degradation rate was up to 97.16%,far larger than that of undoped TiO2 nanotubes(51.11%).Photocatalytic MO degradation on codoped TiO2 nanotubes surface followed first-order kinetics.