Interaction of H2S with alpha-Fe2O3(0001) Surface

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Surface Science

DOI:https://doi.org/10.1016/j.susc.2007.08.011· OSTI ID:959762

Kim, C; Escuadro, A; Bedzyk, M

The atomic-scale structural changes in an {alpha}-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 {alpha}-Fe2O3(0 0 0 1) with a H2S partial pressure of 1 x 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 Angstroms. 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 (SO{sup 2-}{sub 4}) and regenerated the {alpha}-Fe2O3(0 0 0 1) substrate, which was indicated by a (1 x 1) LEED pattern and the re-oxidization of Fe to 3+.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 959762
• Report Number(s): BNL--82748-2009-JA
• Journal Information: Surface Science, Journal Name: Surface Science Vol. 601; ISSN SUSCAS; ISSN 0039-6028
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
ATOMS
HEMATITE
IRON SULFIDES
OXIDATION
OXYGEN
PARTIAL PRESSURE
PHOTOEMISSION
PYRITE
SPECTROSCOPY
STANDING WAVES
SUBSTRATES
SULFATES
SULFIDATION
SULFIDES
SULFUR
SURFACES
VALENCE
national synchrotron light source