N、La共掺杂TiO_2的微观结构及性能

Microstructure and properties of anatase TiO_2 codoped with N and La

采用基于密度泛函理论的平面波超软赝势方法研究了N、La共掺杂TiO2的晶体结构、电子结构和光学性质,计算结果表明,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,且共掺杂后带隙减小,导致光吸收带边红移到可见光区,而电子在La的5d轨道之间的跃迁使共掺杂TiO2在可见光区有较好的光吸收特性。

The crystal structures, electronic structures and optical properties of N or/and La doping anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density func- tional theory. The results showed that the octahedral dipole moments in TiO2 increase due to the changes in lat- tice parameters, bond length and charges on atoms, which was very effective for the separation of photoexcited electron-hole pairs and the improvement of the photocatalytic activity of TiO2. The narrowing band gap results in the red shift of optical absorption edges, and N＋-La codoped TiO2 manifested greater absorption in visible- region.