Formation of O adatom pairs and charge transfer upon O2 dissociation on reduced TiO2(110)

Yingge Du, Nathaniel A. Deskins, Zhenrong Zhang, Zdenek Dohnalek, Michel Dupuis, Igor Lyubinetsky

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Scanning tunneling microscopy and density functional theory have been used to investigate the details of O2 dissociation leading to the formation of oxygen adatom (Oa) pairs at terminal Ti sites. An intermediate, metastable Oa-Oa configuration with two nearest-neighbor O atoms is observed after O2 dissociation at 300 K. The nearest-neighbor Oa pairs are destabilized by Coulomb repulsion of charged Oa‘s and separate further along the Ti row into energetically more favorable second-nearest neighbor configuration. The potential energy profile calculated for O2 dissociation on Ti rows and following Oa‘s separation strongly supports the experimental observations. Furthermore, our results suggest that the itinerant electrons associated with the O vacancies (VO) are being utilized in the O2 dissociation process at the Ti row. Experimentally this is supported by the observation that not all VO‘s can be healed by O2 exposure at 300 K, as some VO‘s becoming less reactive due to supplying certain charge to Oa‘s. Further, theoretical results show that at least two oxygen vacancies per O2 molecule are required in order for the O2 dissociation at the Ti row to become viable.

Original languageEnglish
Pages (from-to)6337-6344
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume12
Issue number24
DOIs
Publication statusPublished - Jan 1 2010

    Fingerprint

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this