Preparation And Optical Properties Of TiO₂Doped With Ions

Energy crisis and environmental pollution are important factors restricting thesustainable economy development of our country, developing the green environmental protection,energy-efficient technology to solve the energy shortage is today’s global strategy. In recent years,due to its chemical stability, security, non-toxic, environmental friendly and can directly use thesolar energy light，TiO2is at the core position in catalysis research, we have made greatprogress in photovoltaic conversion、photochemical synthesis and photocatalysis in environmentalmanagement. The forbidden band width of anatase TiO2is only3.2eV,the ultraviolet light occupyless than3%of sunlight energy can be absorbed in photocatalytic reaction,Solar energy utilizationis low. Through the modification of TiO2to improve the efficiency of photocatalysis, The studiesmainly around the following four aspects: ions doping、rare metal precipitation、semiconductorcompound、organic photosensitization. The above methods effectively avoid the electrons andholes recombination, increase the quantum yield, increase spectral response range and solarenergy utilization. Ion doping is the most common method,but one-component doping can onlyimprove TiO2photocatalysis or one of visible light response factors, co-doping through the way ofsynergy to improve the efficiency of photocatalysis and expand the range of light absorption.Comprehensive above consideration,we use sol-gel method to obtain rare metal doped、transitionmetal doped and co-doped TiO2powder,prepration method and the photocatalytic properties aredeeply studied to provide theoretical and experimental basis of modified TiO2for actualproduction preparation and application. The main work contents are following:1. Transition metals(Fe、Co、Ni) doped TiO2were prepared by sol-gel method.Differentcalcination temperature and doping concentrations are scientific studied that mainly influence theTiO2crystal structure and optical properties. With the increase of transition metal dopingconcentration, TiO2absorption spectra showed red shift phenomenon obviously, in additiontransition metal doping has certain influence on conversion of crystal type.2.Rare earth metals(Sm、Gd、Eu) doped TiO2were prepared by sol-gel method.Differentcalcination temperature and doping concentrations are scientific studied that mainly influence theTiO2crystal structure and optical properties. The study found that the rare metal doping canimprove the spectral response range, the absorption spectrum redshift, and rare earth metal dopinghinders the crystal transformation, improve the stability of the TiO2anatase type zones. 3. Different ions doped TiO2were prepared by sol-gel method， we discussed the theinfluence of different calcination temperature and different ion doping of TiO2crystaltransformation. It was found that doping rare earth elements had a greater influence on the type ofcrystal transformation, transition metal doped TiO2at low temperature can inhibit crystal structuretransformation, the main factors that influence the crystal transformation at high temperature istemperature.4.Rare earth metal Gd3+and transition metal Fe3+codoped TiO2were prepared by sol-gelmethod，we discussed the the influence of different calcination temperature and different metaldoping concentration of Fe,Gd. the study found that codoping adds to the TiO2transformationtemperature.Absorption edge occurred red shift, and the intensity of light absorption increased.