基于密度泛函理论的第一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一定的红移；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。
The crystal structure,electronic structure,optical properties and the band edge position of pure ana-tase TiO2 and anatase TiO2 with S,La single doping and co-doping were investigated by the first principles plane waves ultra-soft pseudopotential.The results showed that crystal lattice constants and bond lengths be-tween atoms and atomic charges of the doped TiO2 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 band when La 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 visible light when S and La were co-doped in TiO2 ,which resulted in oxidation and reduction was enhanced and the photocatalytic efficiency was improved.
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