Preparation And Photocatalytic Performance Of TiO₂ Based Nano Heterojunction

For the problem of pollution and shortage of water resources,human beings are constantly exploring more environmental protection solutions.As a green environmental protection technology,photocatalysis can convert solar energy into chemical energy to deal with water pollution.In the photocatalyst,TiO₂ has excellent performance,but the commercial preparation of titanium dioxide,P25,reaction is carried out under high temperature conditions,the reaction process will appear certain corrosion,so the preparation equipment needs to have corrosion resistance,and the operation technology requirements are high,so it is necessary to find a simple preparation method and high performance TiO₂.In this experiment,the TiO₂ was studied as follows:Firstly,the preparation of TiO₂ nanoplates with different content of HF and calcination temperature,and the comparison of photocatalytic properties.The TiO₂ with sheet structure is synthesized by one-step hydrothermal method,using HF as the morphology control agent and Ti（OC4H9）4 as the precursor.The photocatalytic properties of RhB solution are tested.The TiO₂ films with HF content of 1.5ml and calcined at 600℃ shows high activity.The main reason is that the pore shape appears after calcination,which leads to the increase of specific surface area of the sample,and the competition between the sample and the agglomeration phenomenon after calcination.Secondly,the preparation and photocatalytic properties of TiO₂ nanosheets with different contents of ethanol,alkali washing and calcination are compared.Ti（OC4H9）4 and HF are still used as the preparation agent.In the one-step hydrothermal process,a certain amount of C2H5OH is added,and the resulting samples are washed with alkali.When the C2H5OH is 10ml,and the alkali washed sample shows the best photocatalytic performance.The results show that the addition of a certain amount of C2H5OH increases the dispersion of the reagent,which makes the reaction fully carried out;it is found that the appropriate amount of F-can enhance the photocatalytic performance,while alkali washing can remove the excess F-.Thirdly,the preparation of TiO₂ based nano heterojunction is compared with photocatalytic properties.The photocatalytic properties of TiO₂ also change with the increase of Au addition ratio.When the addition of Au is 1/1000,TiO₂@Au The samples showe the best photocatalytic activity.Because of the electron interaction between TiO₂ and Au,the electrons transfer.It is easier for the electrons of titanium dioxide to transfer to metal,which can inhibit the recombination of the e--h+ of TiO₂.GR dopes TiO₂,among the five groups of graphene samples with different amount of addition,1/1000 TiO₂@GR samples showed excellent catalytic activity.GR is a good electron acceptor,and the potential difference between GR and TiO₂ leads to transfer the TiO₂ electrons to GR surface,which makes the electron hole pair separate.The carbon spheres are doped with TiO₂ and prepared by hydrothermal method.The TiO₂ is controlled by controlling the calcination time for 1 hour to 12 hours TiO₂@C.The content of C in the sample,the calcined sample for 6 hours showes excellent photocatalytic performance.This is because the doping of carbon spheres can reduce the band gap of the sample and improve the utilization and absorption of TiO₂ for light.