Formation of oxygen vacancies on the TiO2(110) surfaces

Density functional theory was employed to investigate the formation and properties of the oxygen vacancies on the rutile TiO2(110) surface. It is found that the formation of the positively charged bridging-oxygen vacancy (BOV+, 4.2 eV) is the most favored one, followed by the positively charged in-plane-oxygen vacancy (POV+, 4.5 eV). In contrast, the formation of the neutral bridging-oxygen and in-plane-oxygen vacancies (BOV and POV), and their dication oxygen vacancies (BOV2+ and POV2+) needs much higher energies (7.9 and 8.3 vs. 8.1 and 8.6 eV), respectively. (C) 2004 Elsevier B.V. All rights reserved.