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Transient Structures of PdO during CO Oxidation over Pd(100)

Shipilin, Mikhail LU ; Gustafson, Johan LU ; Zhang, Chu LU ; Merte, Lindsay LU ; Stierle, Andreas ; Hejral, Uta ; Ruett, Uta ; Gutowski, Olof ; Skoglundh, Magnus and Carlsson, Per-Anders , et al. (2015) In Journal of Physical Chemistry C 119(27). p.15469-15476
Abstract
In situ high-energy surface X-ray diffraction was employed to determine the surface structure dynamics of a Pd(100) single crystal surface acting as a model catalyst to promote CO oxidation. The measurements were performed under semirealistic conditions, i.e., 100 mbar total gas pressure and 600 K sample temperature. The surface structure was studied in detail both in a steady gas flow and in a gradually changing gas composition with a time resolution of 0.5 s. The experimental technique allows for rapid reciprocal 1 space mapping providing the complete information on structural changes of a surface with unprecedented time resolution in harsh conditions. Our results show that the (root 5 x root 5)R27 degrees-PdO(101) surface oxide forms in... (More)
In situ high-energy surface X-ray diffraction was employed to determine the surface structure dynamics of a Pd(100) single crystal surface acting as a model catalyst to promote CO oxidation. The measurements were performed under semirealistic conditions, i.e., 100 mbar total gas pressure and 600 K sample temperature. The surface structure was studied in detail both in a steady gas flow and in a gradually changing gas composition with a time resolution of 0.5 s. The experimental technique allows for rapid reciprocal 1 space mapping providing the complete information on structural changes of a surface with unprecedented time resolution in harsh conditions. Our results show that the (root 5 x root 5)R27 degrees-PdO(101) surface oxide forms in a close to stoichiometric O-2 and CO gas mixture as the mass spectrometry indicates a transition to a highly active state with the reaction rate limited by the CO mass transfer to the Pd(100) surface. Using a low excess of O-2 in the gas stoichiometry, islands of bulk oxide grow epitaxially in the same (101) crystallographic orientation of the bulk PdO unit cell according to a Stranski Krastanov type of growth. The morphology of the islands is analyzed quantitatively. Upon further increase of the O-2 partial pressure a polycrystalline Pd oxide forms on the surface. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry C
volume
119
issue
27
pages
15469 - 15476
publisher
The American Chemical Society (ACS)
external identifiers
  • wos:000357964900072
  • scopus:84936853271
ISSN
1932-7447
DOI
10.1021/acs.jpcc.5b04400
language
English
LU publication?
yes
id
bda42ae9-243a-42c3-8e8d-0e11e78970ff (old id 7783666)
date added to LUP
2016-04-01 10:28:26
date last changed
2022-04-27 22:30:42
@article{bda42ae9-243a-42c3-8e8d-0e11e78970ff,
  abstract     = {{In situ high-energy surface X-ray diffraction was employed to determine the surface structure dynamics of a Pd(100) single crystal surface acting as a model catalyst to promote CO oxidation. The measurements were performed under semirealistic conditions, i.e., 100 mbar total gas pressure and 600 K sample temperature. The surface structure was studied in detail both in a steady gas flow and in a gradually changing gas composition with a time resolution of 0.5 s. The experimental technique allows for rapid reciprocal 1 space mapping providing the complete information on structural changes of a surface with unprecedented time resolution in harsh conditions. Our results show that the (root 5 x root 5)R27 degrees-PdO(101) surface oxide forms in a close to stoichiometric O-2 and CO gas mixture as the mass spectrometry indicates a transition to a highly active state with the reaction rate limited by the CO mass transfer to the Pd(100) surface. Using a low excess of O-2 in the gas stoichiometry, islands of bulk oxide grow epitaxially in the same (101) crystallographic orientation of the bulk PdO unit cell according to a Stranski Krastanov type of growth. The morphology of the islands is analyzed quantitatively. Upon further increase of the O-2 partial pressure a polycrystalline Pd oxide forms on the surface.}},
  author       = {{Shipilin, Mikhail and Gustafson, Johan and Zhang, Chu and Merte, Lindsay and Stierle, Andreas and Hejral, Uta and Ruett, Uta and Gutowski, Olof and Skoglundh, Magnus and Carlsson, Per-Anders and Lundgren, Edvin}},
  issn         = {{1932-7447}},
  language     = {{eng}},
  number       = {{27}},
  pages        = {{15469--15476}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Journal of Physical Chemistry C}},
  title        = {{Transient Structures of PdO during CO Oxidation over Pd(100)}},
  url          = {{http://dx.doi.org/10.1021/acs.jpcc.5b04400}},
  doi          = {{10.1021/acs.jpcc.5b04400}},
  volume       = {{119}},
  year         = {{2015}},
}