Water adsorption on α-Fe2O3 (0001) at near ambient conditions
Artikel i vetenskaplig tidskrift, 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

Författare

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, Teknisk fysik, Kemisk fysik

D. E. Starr

Lawrence Berkeley National Laboratory

Brookhaven National Laboratory

E. R. Mysak

Lawrence Berkeley National Laboratory

K. J. Andersson

Danmarks Tekniske Universitet (DTU)

Stockholms universitet

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

Stockholms universitet

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 114 5 2256-2266

Ämneskategorier

Fysik

DOI

10.1021/jp909876t