(S,Co)双掺杂TiO_2改性第一性原理

Density function theory on performance increase of TiO_2 codoped with S and Co

为提高TiO2晶体的光催化性能,采用基于密度泛函理论的平面波超软赝势方法,研究了S和Co分别单掺杂和双掺杂锐钛矿TiO2的晶体结构、电子结构和光学性质.研究结果表明:原子替位掺杂后体系晶格畸变较小;禁带中杂质能级的出现使TiO2光吸收带边发生了明显红移,且在可见光区的吸收效率显著增加,大大提高了光催化效率.与单掺杂比较发现,(S,Co)双掺杂红移现象更加明显且在可见光区均有吸收,为较好的掺杂改性方式.该成果对实验合成性能较佳的TiO2具有较好的指导意义.

To improve the photocatalytic activity of TiO2, the crystal structure, electronic structure and optical properties of S, Co, and （S, Co）-codoped anatase TiO2 are investigated based on the plane-wave ultrasoft pseudoptential method in the density functional theory. The results indicate that due to S and Co atoms occupy the O and Ti sites in anatase TiO2, the lattice has less distortions. Also, some impurity bands appear in the forbidden band gap, which leads to the red shift of the optical absorption edge and the increase of the coefficient of light absorption, therefore further increases the photocatalytic activity under visible-light irradiation. Due to the significant red shift and coefficient of light absorption, （S, Co） codoped TiO2 is the best choice of capabilities improvement. The results provide a good guide for the TiO2experimental synthesis.