非金属掺杂改性TiO_2光催化剂的机理

Nonmetal Element Doping Mechanisms of Titanium Oxide Photocatalyst

为了扩展TiO2光催化剂对可见光的利用,以非金属元素对其进行掺杂和改性是近年来很活跃的研究内容,文献报道主要有氮、碳、硫、氟等非金属元素的改性结果。各种不同的改性方法如高温气氛还原、脉冲激光沉积、离子溅射、机械化学、溶液湿法等都可以得到非金属元素改性。本文重点探讨了氮改性TiO2光催化剂的结果,氮改性TiO2的方法和改性机理,讨论了氮改性TiO2的结构及其对可见光的利用机理等,对碳、硫、氟等元素掺杂改性也作了简要介绍。

In order to obtain visible light response, doping or modifying titania by nonmetal elements such as nitrogen has been investigated extensively in recent years. In this paper, recent progress in mechanism of titania doping by nitrogen, carbon, sulphur, fluorine is reviewed. Methods for preparing nitrogen doped titania are follows： i） reduce titania by ammonia gas under high temperature; ii）sputter titania target in nitrogen gas; iii）pulsed laser deposition in nitrogen gas; iv） mechanochemical processing titania in ammonia; v）direct oxidation titanic nitride; vi）forming organic titanic nitride and then thermal treated; vii）hydrolysis a titanic precursor in ammonia solution then thermal treated the precipitate. Structure and mechanism of visible light response of the nitrogen doped titania are discussed according to literature reports although there had many inconsistent conclusions. Narrowing the band gap of titania or forming a new isolated level in band gap may be the most probable reason for visible response. Titania doping by carbon, sulphur or fluorine can also give rise to visible light response and high photo efficiency, but there had many inconsistent conclusions too.