Preparation And Photocatalytic Properties Of Ag/AgCl/TiO₂ And BiOBr Visible-light Photocatalysts

Semiconductor photocatalysis can be decomposed into water to produce hydrogen,and degrade some pollutants in water and air,so photocatalytic technology has attracted more and more attention in the field of environmental protection and new energy production.In order to overcome the defects of TiO₂?too large band gap and too narrow spectral response range?,how to modify traditional TiO₂ and develop new visible light catalysts has become a hotspot issues.There are many methods to enhance TiO₂ visible light catalytic activity,such as metal and nonmetal ion doping,noble metals loading,semiconductor composite and dye sensitization.As a kind of visible-light photocatalysts,bismuth oxyhalides Bi OX?X=F,Cl,Br,I?has high degree of anisotropy,unique layered structure,good optical-absorption properties and efficient visible light catalytic activity,there are great potential in photocatalytic field.Among of them,Bi OBr has the most reasonable band gap and strong chemical stability,is a very ideal photocatalyst.The main work of this research is improve the photocatalytic activity of TiO₂ by noble metals loading and explore some simple and efficient method for preparing Bi OBr.Chapter 1 introduce the development process,reaction principle,application fields and research status of semiconductor photocatalysis.Chapter 2 is TiO₂ modification by noble metals loading.We deposit Ag/Ag Cl particles onto the surface of TiO₂ hollow microspheres by deposition method and photoreduction method.The material has a high purity,good morphology and photochemical properties,because of the localized surface plasmon resonance,we extend the spectral response range of TiO₂ to visible region successfully.In chapter 3,we prepared flower-like Bi OBr nanomaterials by a simple,efficient,green hydrothermal method.The material has a high purity,good crystallinity,and can generate a large amount of electron-hole pairs when excited by visible-light irradiation.So it has good photocatalytic activity,is higher than the Bi OBr prepared by solvothermal method using ethylene glycol as solvent.In chapter 4,we obtained an ultrathin nanosheet structure Bi OBr by a rapid,simple,efficient and low-cost hydrolysis method.The material has high purity,good crystallinity,good dispersion,good light absorption and photoelectrochemical properties,which make it has a very high catalytic activity.Its photocatalytic activity is higher than the P25 TiO₂ and the Bi OBr prepared by solvothermal method using ethylene glycol as solvent.Chapter 5 is the article summarized,we also point out some unresolved issues about photocatalytic degradation of organic pollutants.