Preparation And Photoelectrochemical Performance Study Of Cr³⁺-Doped TiO₂ Film

With the continuous development of human society economy,serious environmental pollution and excessive energy consumption are two difficulties for humanbeing.Therefore,it is the most effective way to solve these two problems by developing clean and renewable energy.Nowadays,many researchers found that photocatalytic water splitting hydrogen production is one of the most promising technology.In all kinds of metal oxide semiconductor materials,Titanium dioxide?TiO₂?has been widely applied to photocatalytic water splitting hydrogen production,degradation of organic pollutants,disinfection sterilization,etc,due to the strong oxidation ability,low price,nontoxic,stable properties,etc.However,the application range of TiO₂ has been limited due to the high electronic-hole recombination rate and low visible light response.Hence,the study of the modification of TiO₂ to improve the photocatalytic activity is a topic of concern.In many modification methods,transition metal ions doped has significant advantages.The ionic radius of Cr³⁺ and Ti4+ is similar,so that it is easier to replace Ti.After years of research,there are a lot of the preparation method of Cr³⁺-TiO₂,such as: magnetron sputtering method,hydrothermal method,sol-gel method,and so on.The main purpose of this article is elaborates the two new preparation methods of Cr³⁺-TiO₂,and its various performance have been characterized.Specific work is as follows:1.Preparation of the amorphous TiO₂ using the method of magnetron sputtering,then preparation of Cr³⁺-TiO₂ thin film with different Cr³⁺ concentration by the hydrothermal diffusion method.All films were annealed in air at 400 oC and 500 oC.The XPS date shows that extending the hydrothermal time can increase Cr³⁺ concentration.With the increase of the concentration of the Cr³⁺,the photocurrent density and the IPCE values of the films are improved.The Raman date shows that the film annealed at 500? shows favorable crystallinity,while low annealed temperature of 400 oC lead to a poor crystallinity.The highest photocurrent density and IPCE value of Cr³⁺-TiO₂ film is 410 ?A/cm2 and 0.43%,respectively.2.Electirc field can be bulit in film by gradient doping Cr³⁺.It is contribute to promote the electron-hole separation.In this work,we hoose the FTO with Cr2O3 as the base for preparation TiO₂ thin film by dip-coating method on the substrate.The thin film is annealed treatment under the condition of air,which makes the Cr element diffusion into the TiO₂ thin film to complete the doping.In order to explore different annealing temperature on the influence of the doping level,set respectively in this paper,the annealing temperature is 400 ?,450 ? and 500 ?.The study found that after 500 ? annealing treatment of the film has good photoelectrochemistry performance.