Transient stuctures of PdO during CO oxidation over Pd(100)
Artikel i vetenskaplig tidskrift, 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.
SXRD
heterogeneous catalysis
PdO
CO oxidation
islands
HESXRD
Pd
Författare
Mikhail Shipilin
Lunds universitet
Johan Gustafson
Lunds universitet
Chu Zhang
Lunds universitet
Lindsay R. Merte
Lunds universitet
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
Kompetenscentrum katalys
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Per-Anders Carlsson
Kompetenscentrum katalys
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Edvin Lundgren
Lunds universitet
Journal of Physical Chemistry C
1932-7447 (ISSN) 1932-7455 (eISSN)
Vol. 119 27 15469-15476Tidsupplösta in situ metoder för design av katalytiska säten för hållbar kemi
Vetenskapsrådet (VR) (2013-567), 2013-01-01 -- 2016-12-31.
Drivkrafter
Hållbar utveckling
Styrkeområden
Nanovetenskap och nanoteknik
Transport
Energi
Materialvetenskap
Ämneskategorier
Fysikalisk kemi
Den kondenserade materiens fysik
DOI
10.1021/acs.jpcc.5b04400