Study On Photoelectric Performance Of SrTiO₃/TiO₂ And Doping Mechanism Of Cr-Doped Srtio₃

Strontium titanate（SrTiO₃）possesses the merits of chemical stability,low toxicity and reasonable redox potential,endowing it with significant application potentials in photocatalytic hydrogen evolution.But its wide band gap,high charge recombination rate,and low solar energy conversion efficiency inhibit its application and development in the fields of photocatalysis and photoelectrocatalysis.Therefore,it is imperative to modify SrTiO₃to improve its photocatalytic and photoelectrocatalytic properties.In this paper,SrTiO₃/Ti O₂photoelectrode and Cr-doped SrTiO₃（abbreviated as STO（Cr））photocatalyst were synthesized by different methods and characterized to establish a relationship between the preparation method,the position of doped atom,visible light absorption and photocatalytic and photoelectrocatalytic performance.The main research contents of this paper are as follows:（1）A series of SrTiO₃/Ti O₂ heterojunction photoelectrodes were prepared by using a two-step anodic oxidation-solvothermal method.The obtained SrTiO₃/Ti O₂photoelectrodes displayed visible light response,which were probably attributed to the generation of oxygen vacancies.It was found that the component of photoelectrode can be adjusted by varying the time and temperature of the solvothermal reaction,leading to the flexible tuning of the carrier density and photoelectric performance.Besides,the photocurrent density of SrTiO₃/Ti O₂ photoelectrodes were assessed.The results suggested that the SrTiO₃/Ti O₂-130-20 showed the best photoelectric performance,which was ascribed to heterojunction formation and oxygen vacancies production.（2）STO（Cr）photocatalyst was synthesized by sol gel hydrothermal method,polymerization complexation method and oil bath method,respectively.It was found that the STO（Cr）prepared by sol gel hydrothermal method displayed efficient photocatalytic performance for hydrohen production,while the activity of STO（Cr）prepared by polymerization complexation and oil bath methods was almost negligible.In order to reveal the significant difference of photocatalytic activity,the valence state,the coordination environment and the position of doped Cr in different samples were analyzed.The doping mechanism of Cr was preliminarily explored.