Studies On The Preparation And Properties Of Some Photocatalytic Nanocomposites

People are in the face of the rigorous challenge of population,resources,energy and environment problem in 21 century,especially pollution of the environment and lack of energy is the most important problem among them.Recently,the semiconductor photo-catalytic oxidation technique applied in degradation of environment pollution is one of the researching hotspot by environmental investigator in the whole world; namo-TiO₂ has been the focus of the investigations,particularly because of its advantages of stability,low cost,high photo-catalytic efficiency and extensive application.This thesis mainly consists of four major parts:Part 1:This part systemically reviewed the development and the existent problem of the photochemical catalysis material.The application,modification,preparation and carrier research situation of the manometer Ti02 photochemical catalysis technology are described in detail.In addition,the doping,the carrier preparation methods,the photochemical catalysis activeness of the manometer Ti02 photocatalyst were roundly introduced.Part 2:Pr₂O₃ doped TiO₂ composite nanoparticles with different Pr2O₃ content were successfully synthesized by a sol-gel process using Ti(OC₄H₉)₄ as raw material and also characterized by means of XRD,TG-DTA,AFM,UV-Vis and FIRT.The photocatalytic activity of Pr₂O₃/TiO₂ was evaluated by the photocatalytic degradation of acid fuchsine.The influential factors on photocatalytic activity of Pr₂O₃/TiO₂,such as the content of Pr₂O₃,the temperature and pH value were investigated.It is found that and the optimum amount of Pr₂O₃/ TiO₂ was obtained at 0.04g/25ml at the optimal conditions(Pr/Ti=0.8%).It has been shown that with the doping of Pr₂O₃ the particle diameter of Pr₂O₃/TiO₂ samples decreased,the specific surface area increased while the photocatalytic activity was strengthened.Part 3:La-TiO₂/montmorillonite(La-TiO₂/MMT)composite photocatalyst is synthesized by a sol-gel process using Ti(OC₄H₉)4 as raw material to introduce nanosized TiO2 and La₂O₃ into the interlayer space of montmorillonite(MMT).In order to obtain pillared La-TiO2/MMT with stable structure,the sample was calcined at 500℃.The physico-chemical properties of the composite photocatalyst,such as phase composition,specific surface area,element content etc.,are characterized using XRD,IR techniques.The photocatalytic activity form fuchsine degradation is as follows:La-TiO2/MMT＞TiO2/MMT＞TiO2.Among them the La-TiO2/MMT has the highest photocatalytic activity because of its larger specific surface area caused by pillaring and modification by lanthanum.Part 4:A series of LaFe_1-xCo_xO₃(x=0,1/3,2/3,1)compounds were prepared by citrate sol-gel method.The LaFe_1-x,Co_xO₃ were studied with XRD,IR and UV techniques.The photodegradation experiments of soluble dyes were carried out in the suspension of LaFe_1-xCo_xO₃ acting as the photocatalysts.The influence of doping on photocatalytic activity was also investigated in detail.The results show that the doping can greatly improve the photocatalytic activity,and the photocatalytic activity of LaFe_1/3Co_2/3O₃ was the best one in LaFe_1-xCo_xO₃(x=0,1/3,2/3,1)compounds.