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Atmospheric pressure oxidation of Pt(111)
DOI:
10.1088/0953-8984/20/18/184013
Authors:
C.
Ellinger
(Max-Planck-Institut für Metallforschung)
,
A.
Stierle
(Max-Planck-Institut für Metallforschung)
,
A.
Nefedov
(Ruhr-Universität Bochum)
,
H.
Dosch
(Max-Planck-Institut für Metallforschung)
,
I. K.
Robinson
(Diamond Light Source)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Journal Of Physics: Condensed Matter
, VOL 20
, PAGES 184013
State:
Published (Approved)
Published:
May 2008
Abstract: The oxidation of the platinum (111) single crystal surface and the formation of platinum dioxide have been studied by in situ surface x-ray diffraction and x-ray reflectivity. At an oxygen partial pressure of 500 mbar and at temperatures from 520 to 910 K, the experiments disclose the growth of two atomic layers of a bulk-like, strongly distorted α-PtO2. The epitaxial Pt oxide layer is oriented hexagon on hexagon with respect to the Pt(111) surface leading to a (8 × 8) superstructure surface unit cell. In a second SET of experiments, a 100 Å thick epitaxial Pt(111) film on sapphire was exposed to oxygen. At 670 K and near atmospheric oxygen pressures we find the formation of a several angstrom thick oxide layer. After annealing the sample at 720 K in a vacuum the oxide layer desorbs, recovering the 100 Å thick Pt film. Subsequent oxidation at 720 K and reduction cycles lead to a slight increase in surface roughness and the formation of macroscopically visible holes in the Pt film. These results point to a Pt re-dispersion which sets in during chemical reactions at atmospheric pressures.
Subject Areas:
Physics
Instruments:
NONE-No attached Diamond beamline
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