Adsorption of V on a hematite (0 0 0 1) surface and its oxidation: Submonolayer coverage

Jianjian Jin, Xiaoyan Ma, C. Y. Kim, Donald E Ellis*, Michael J Bedzyk

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

The adsorption of submonolayer V on an idealized model hematite (0 0 0 1) surface and subsequent oxidation under atomic O adsorption are studied by density functional theory. The preferred adsorption sites, adsorption energy and configuration changes due to V and O adsorption are investigated. It is found that in most cases V forms threefold bonds with surface O atoms, inducing a large geometry change at the hematite surface and near surface region and a bond stretch between surface Fe and O. The adsorption energy is mainly decided by interplay between adsorbed metal-surface oxygen bonding and adsorbed metal - subsurface metal interaction. The relative energy of subsequent O adsorption and geometry depends on the reformed V/hematite structure. Electronic properties such as projected densities of states and chemical state change upon V adsorption are studied through both periodic slab and embedded cluster localized orbital calculations; both strong vanadium-oxygen and vanadium-iron interactions are found. While V generally donates electrons to a hematite surface, causing nearby Fe to be partially reduced, the Fe and V oxidization state depends very much on the coverage and detailed adsorption configuration. When the V/hematite system is exposed to atomic O, V is further oxidized and surface/near surface Fe is re-oxidized. Our theoretical results are compared with X-ray surface standing wave and X-ray photoelectron spectroscopic measurements. The influence of d-electron correlation on the predicted structures is briefly discussed, making use of the DFT + U scheme.

Original languageEnglish (US)
Pages (from-to)3082-3098
Number of pages17
JournalSurface Science
Volume601
Issue number14
DOIs
StatePublished - Jul 15 2007

Keywords

  • Density functional theory
  • Hematite
  • Surface oxidation
  • Vanadium adsorption

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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