Water adsorption on α-Fe2O3 (0001) at near ambient conditions

Susumu Yamamoto, Tom Kendelewicz, John T. Newberg, Guido Ketteler, David E. Starr, Erin R. Mysak, Klas J. Andersson, Hirohito Ogasawara, Hendrik Bluhm, Miquel Salmeron, Gordon E. Brown, Anders Nilsson

Research output: Contribution to journalArticlepeer-review

181 Citations (Scopus)

Abstract

We have investigated hydroxylation and water adsorption on α Fe 2O3(0001) at water vapor pressures up to 2 Torr and temperatures ranging from 277 to 647 K (relative humidity (RH) < 34%) using ambient-pressure X-ray photoelectron spectroscopy (XPS). Hydroxylation occurs at the very low RH of 1 × 10-7 % and precedes the adsorption of molecular water. With increasing RH, the OH coverage increases up to one monolayer (ML) without any distinct threshold pressure. Depth profiling measurements showed that hydroxylation occurs only at the topmost surface under our experimental conditions. The onset of molecular water adsorption varies from ∼2 ×10-5 to ∼4 ?10-2 % RH depending on sample temperature and water vapor pressure. The coverage of water reaches 1 ML at ∼15% RH and increases to 1.5 ML at 34% RH.

Original languageEnglish
Pages (from-to)2256-2266
Number of pages11
JournalJournal of Physical Chemistry C
Volume114
Issue number5
DOIs
Publication statusPublished - 2010 Feb 11
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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