Preparation And Photocatalytic Properties Of P-TiO₂ And TiO₂/BiOI Heterostructures

Photocatalyst has become an attracted research in recent years.Among them,the TiO₂ photocatalyst and the heterogeneous structure have attracted more and more attention.However,TiO₂ can only be excited by UV light because of its large band gap.As a result,it is pretty important to report nano titanium dioxide catalyst of Ion doped and the catalyst which composited with two kinds of materials.Nano titanium dioxide photocatalyst with doping phosphorus and TiO₂/Bi OI catalyst are particularly of concern.The catalyst which doped phosphorus is beneficial to the absorption of visible light and shows some stability characteristics under high temperature.What's more,the study of TiO₂-Bi OI composite samples in the preparation of the heterogeneous structures has also achieved good results.Two materials are combined to form p-n junctions,therefore visible light can be used efficiently to degradate the organic pollutants under visible light.In this paper,boiling reflux method was used to prepare for P-TiO₂ sample.We used Ti Cl4 as titanium source,Na H2PO4 as dopant to prepared P-TiO₂ photocatalyst with different doping concentration.The particle size of 6%P-TiO₂ sample is about 6nm,and the particle size of the prepared sample is small,which belongs to TiO₂ quantum dots.The samples were calcined under high temperature calcination temperature in a muffle furnace.XPS,XAFS,XAS and other characterization methods were used to discuss the microstructure and electronic energy band structure of P-TiO₂ samples.TiO₂/Bi OI samples were prepared by chemical precipitation method at room temperature.The crystal phase composition,morphology and internal structure of P-TiO₂ and TiO₂/Bi OI were studied by using XRD,SEM,TEM,BET,XPS and other characterization methods in the experiment.The optical properties of the samples were studied by UV-diffuse reflectance.And the visible light catalytic activity was investigated by degradation of methyl orange and rhodamine B.The research results are as follows:1? The samples wih the doping amount of 4%¹0% were all show pure anatase phase,and the particle size of the samples doped with phosphorus were small.P-doped TiO₂ samples were calcinated at high temperature.With the increasement of calcination temperature,The sample gradually changed from anatase to rutile.The samples doped with P greatly2? improved the stability of anatase phase at high temperature.Methyl orange and Rhodamine B were used as the simulation of pollutants,The photocatalytic oxidation of the samples doped with P has been improved obviously.And the amount of 6% is the best doping amount.The samples calcined at high temperature still maintained a good photocatalytic activity.The degradation rate of 6%P-TiO₂ was 75.7% under the high tempertature of 1080?.3? XPS?XAFS and XAS results indicated that P atoms have been permeated into the lattice of TiO₂,The samples after calcination gradually formed rutile phase,P5+replaced part of the Ti4+and formed a Ti-O-P bond4? When the amout of TiO₂ reached a certain time,the results of XRD showed the characteristic peaks of Bi OI and TiO₂ for the sample of TiO₂/Bi OI.The increase of the amount of TiO₂ was favorable for the growth of Bi OI along?110?crystal surface.In the composite sample of TiO₂/Bi OI,Bi OI was presented in a patchy structure and TiO₂ was presented in spherical.Methyl orange and Rhodamine B were used as the simulation of pollutants,The photocatalytic properties of the composite samples were better than that of the single Bi OI samples and TiO₂ samples.The photocatalytic of 60%TiO₂/Bi OI was the best.The degradation rate of 60%TiO₂/Bi OI was 98% in 40 minutes.