Transient stuctures of PdO during CO oxidation over Pd(100)
Journal article, 2015
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 semi-realistic 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 ow and in a gradually changing gas composition with a time resolution of 0.5 sec. Our results show that \sqroot-PdO(101) surface oxide forms in a close to stoichiometric O2 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 O2 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 O2 partial pressure a polycrystalline Pd oxide forms on the surface.
HESXRD
CO oxidation
SXRD
Pd
PdO
heterogeneous catalysis
islands
Author
Mikhail Shipilin
Lund University
Johan Gustafson
Lund University
Chu Zhang
Lund University
Lindsay R. Merte
Lund University
Andreas Stierle
Deutsches Elektronen-Synchrotron (DESY)
Uta Hejral
Deutsches Elektronen-Synchrotron (DESY)
Uta Ruett
Deutsches Elektronen-Synchrotron (DESY)
Olof Gutowski
Deutsches Elektronen-Synchrotron (DESY)
Magnus Skoglundh
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry
Competence Centre for Catalysis (KCK)
Per-Anders Carlsson
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry
Competence Centre for Catalysis (KCK)
Edvin Lundgren
Lund University
Journal of Physical Chemistry C
1932-7447 (ISSN) 1932-7455 (eISSN)
Time-resolved in situ methods for design of catalytic sites within sustainable chemistry
Swedish Research Council (VR), 2013-01-01 -- 2016-12-31.
Driving Forces
Sustainable development
Areas of Advance
Nanoscience and Nanotechnology (2010-2017)
Transport
Energy
Materials Science
Subject Categories
Physical Chemistry
Condensed Matter Physics
DOI
10.1021/acs.jpcc.5b04400