A series of Ti-doped SnO2(110) surfaces with different oxygen vacancies have been investigated by means of first principles DFT calculations combined with a slab model. Three kinds of defective SnO2(110) surfaces are considered, including the formations of bridging oxygen (Ob) vacancy, in-plane oxygen (Oi) vacancy, and the coexistence of Ob and Oi vacancies. Our results indicate that Ti dopant prefers the fivefold-coordinated Sn site on the top layer for the surface with Ob or Oi vacancy, while the replacement of sublayer Sn atom becomes the most energetically favorable structure if the Ob and Oi vacancies are presented simultaneously. Based on analyzing the band structure of the most stable configuration, the presence of Ti leads to the variation of the band gap state, which is different for three defective SnO2(110) surfaces. For the surface with Ob or Oi vacancy, the component of the defect state is modified, and the reaction activity of the corresponding surface is enhanced. Hence, the sensing performance of SnO2 may be improved after introducing Ti dopant. However, for the third kind of reduced surface with the coexistence of Ob and Oi vacancies, the sublayer doping has little influence on the defect state, and only in this case, the Ti doping state partly appears in the band gap of SnO2(110) surface.
Bibliographical noteFunding Information:
This work was supported by National Natural Science Foundations of China (grant nos. 21073035, 21071031, 90922022, and 21171039). Y. Z. and W. C. also would like to thank the programs for New Century Excellent Talents in University of Fujian Province (grant nos. HX2006-97, HX2006-103). We are grateful for the generous allocation of computer time on the high-performance computer center of Fujian Province.
- Band structure
- Defect state
- Density functional theory
- Tin dioxide