Interaction of H2S with α-Fe2O3(0 0 0 1) surface

Chang Yong Kim*, Anthony A. Escuadro, Michael J. Bedzyk

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

The atomic-scale structural changes in an α-Fe2O3 (hematite) (0 0 0 1) surface induced by sulfidation and subsequent oxidation processes were studied by X-ray photoemission spectroscopy, LEED, and X-ray standing wave (XSW) measurements. Annealing the α-Fe2O3(0 0 0 1) with a H2S partial pressure of 1 × 10-7 Torr produced iron sulfides on the surface as the sulfur atoms reacted with the substrate Fe ions. The oxidation state of the substrate Fe changed from 3+ to 2+ as a result of the sulfidation. The XSW measured distance of the sulfur atomic-layer from the unrelaxed substrate oxygen layer was 3.16 Å. The sulfide phase consisted of three surface domains identified by LEED. Formation of the two-dimensional FeS2 phase with structural parameters consistent with an outermost layer of (1 1 1) pyrite has been proposed. Atomic oxygen exposure oxidized the surface sulfide to a sulfate (SO42 -) and regenerated the α-Fe2O3(0 0 0 1) substrate, which was indicated by a (1 × 1) LEED pattern and the re-oxidization of Fe to 3+.

Original languageEnglish (US)
Pages (from-to)4966-4970
Number of pages5
JournalSurface Science
Volume601
Issue number21
DOIs
StatePublished - Nov 1 2007

Keywords

  • Hematite
  • Hydrogen sulfide
  • Pyrite
  • Surfaces
  • X-ray standing waves

ASJC Scopus subject areas

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

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