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Characterization of supported Pd catalysts
Author(s) -
Papp H.,
Kamp P.
Publication year - 1988
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740120405
Subject(s) - chemisorption , physisorption , catalysis , carbon monoxide , x ray photoelectron spectroscopy , chemistry , adsorption , partial pressure , activation energy , metal , dispersion (optics) , transition metal , inorganic chemistry , analytical chemistry (journal) , chemical engineering , oxygen , organic chemistry , physics , optics , engineering
Supported Pd catalysts are active for the oxidation of carbon monoxide at low temperature. To understand the catalytic action on a molecular basis, catalysts with different metal loadings have been investigated by activity tests with regard to CO 2 formation, by CO chemisorption, N 2 physisorption and XPS measurements. The rate of CO 2 formation turns out to be independent of CO partial pressure and dependent on O 2 partial pressure (0.3 order) in the pressure and temperature range investigated. The activation energy of CO oxidation has a value of 40 kJ mol −1 independent of metal loading. The specific surface are and the pore structure of the support is not significantly changed even by a metal loading as high as 17 weight per cent. The irreversibly adsorbed amount of CO—determined at 273 K in a vacuum microbalance—is linearly related to the CO 2 formation rate. The dispersion determined by XPS measurements is proportional to that calculated from the CO chemisorption results.