中文摘要：

基于密度泛函理论的第-性原理平面波超软赝势方法研究了纯TiO2、S和La分别单掺杂及共掺杂锐钛矿相TiO2 的晶体结构、电子结构、光学性质及带边位置,结果表明,S掺杂后TiO2 的晶格常数、原子间的键长和原子电荷都发生了变化,导致掺杂后的八面体偶极矩增加,从而有利于光生电子-空穴对的分离,提高TiO2 的光催化性能;S掺杂TiO2 禁带中出现杂质能级,从而将TiO2 的光谱响应红移至可见光区;La掺杂TiO2 杂质能级出现在导带而非禁带中,带隙有所减小,吸收光谱的阈值波长发生了-定的红移;而S、La共掺杂TiO2 的光谱响应范围向可见光区明显拓展,且氧化还原能力增强,因此S、La共掺杂可显著提高TiO2 光催化性能.

英文摘要：

The crystal structure, electronic structure, optical properties and the band edge position of pure ana tase TiO2 and anatase TiO2 with S, I.a single doping and co-doping were investigated by the first principles plane waves ultra soft pseudopotential. The results showed tlqat crystal lattice constants and bond lelqgths be tween atoms and atomic charges of the doped TiOz were changed, which caused the surface of the body eight di pole moment increase. This method was favorable for effective separation of photo generated electron hole pairs and would improve the photocatalytic performance of TiO2. The band gap appears impurity level when S was doped in TiO2 so that the absorption threshold wavelength red shifts to visible light region. However, impurity level appeared in the conduction hand when ha was doped in TiO2 rather than the band gap, with band gap de creasing, the absorption spectrum threshold wavelength red shifted a little. Spectral response range extended to