CO Oxidation on Technological Pd-Al2O3 Catalysts: Oxidation State and Activity
Journal article, 2011

The specific CO oxidation activity of palladium versus palladium oxide is still controversially discussed. In this study, 5 wt. % Pd-gamma-Al2O3 catalysts were utilized to investigate the effect of the palladium oxidation state on the CO oxidation activity. Comprehensive in situ and ex situ characterization of different alumina supported PdOx (x = 0-1) phases (by HR-TEM, XRD, and FTIR spectroscopy), combined with kinetic measurements and DFT calculations of CO adsorption, allowed us to assess the catalytic activity of the different PdOx (x = 0-1) species: Supported Pd-0 and substoichiometric PdOx<1 exhibited comparable high activities, due to a rapid reduction of PdOx<1 to Pd upon CO exposure. PdO nanoparticles showed a lower catalytic activity resulting from their higher stability against reduction by CO. The limited extent of oxidation of Pd under typical reaction conditions together with the facile reduction of substoichiometric PdOx<1 suggest that the active phase present under the current reaction conditions is oxygen-covered metallic Pd.

pd nanoparticles

model catalysts


sum-frequency generation

reflection-absorption spectroscopy

supported palladium catalysts


functional theory calculations

single-crystal surfaces




K. Zorn

Vienna University of Technology

S. Giorgio

Centre national de la recherche scientifique (CNRS)

E. Halwax

Vienna University of Technology

C. R. Henry

Centre national de la recherche scientifique (CNRS)

Henrik Grönbeck

Competence Centre for Catalysis (KCK)

Chalmers, Applied Physics, Chemical Physics

G. Rupprechter

Vienna University of Technology

Journal of Physical Chemistry C

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

Vol. 115 4 1103-1111

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)


Materials Science


Basic sciences

Subject Categories

Atom and Molecular Physics and Optics

Chemical Sciences



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Latest update

9/7/2018 1