Water adsorption on α-Fe2O3 (0001) at near ambient conditions
Journal article, 2010
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.
Threshold pressures
Experimental conditions
Sample temperature
Water adsorption
Molecular water
Relative humidities
Author
S. Yamamoto
FOM Institute for Atomic and Molecular Physics - AMOLF
Stanford Synchrotron Radiation Laboratory
T. Kendelewicz
Stanford University
J. T. Newberg
Lawrence Berkeley National Laboratory
Guido Ketteler
Chalmers, Applied Physics, Chemical Physics
D. E. Starr
Lawrence Berkeley National Laboratory
Brookhaven National Laboratory
E. R. Mysak
Lawrence Berkeley National Laboratory
K. J. Andersson
Technical University of Denmark (DTU)
Stockholm University
Stanford Synchrotron Radiation Laboratory
H. Ogasawara
Stanford Synchrotron Radiation Laboratory
H. Bluhm
Lawrence Berkeley National Laboratory
M. Salmeron
Lawrence Berkeley National Laboratory
University of California
G. E. Brown Jr
Stanford Synchrotron Radiation Laboratory
Stanford University
A. Nilsson
Stanford Synchrotron Radiation Laboratory
Stanford University
Stockholm University
Journal of Physical Chemistry C
1932-7447 (ISSN) 1932-7455 (eISSN)
Vol. 114 5 2256-2266Subject Categories
Physical Sciences
DOI
10.1021/jp909876t