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.

CO oxidation

PdO

SXRD

Pd

HESXRD

islands

heterogeneous catalysis

Författare

Mikhail Shipilin

Johan Gustafson

Chu Zhang

Lindsay R. Merte

Andreas Stierle

Uta Hejral

Uta Ruett

Olof Gutowski

Magnus Skoglundh

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Per-Anders Carlsson

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Teknisk ytkemi

Kompetenscentrum katalys (KCK)

Edvin Lundgren

Journal of Physical Chemistry C

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

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Transport

Energi

Materialvetenskap

Ämneskategorier

Fysikalisk kemi

Den kondenserade materiens fysik

DOI

10.103/acs.jpcc.5b04400

Mer information

Skapat

2017-10-08