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Influence of Potassium on the Oxidation Rate of Carbon

Published online by Cambridge University Press:  28 February 2011

Peter Sjövall ,
Bo Hellsing ,
Karl-Erik Keck  and
Bengt Kasemo
Peter Sjövall
Affiliation:
Chalmers University of Technology, Department of Physics, S-412 96 Gidteborg, Sweden
Bo Hellsing
Affiliation:
Chalmers University of Technology, Department of Physics, S-412 96 Gidteborg, Sweden
Karl-Erik Keck
Affiliation:
Chalmers University of Technology, Department of Physics, S-412 96 Gidteborg, Sweden
Bengt Kasemo
Affiliation:
Chalmers University of Technology, Department of Physics, S-412 96 Gidteborg, Sweden
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Abstract

The influence of K, deposited on a carbon surface, on the oxidation of carbon in O2 was investigated. Reaction rate measurements, carried through in a UHV-system by use of AES, showed that potassium increases the reaction rate by up to ∼ 104 times. A theoretical model, based on the assumption that O2 dissociation is the rate limiting step, has been developed. The model shows that a charge transfer mechanism can explain the observed rate increase. Results from TPD/TPR-measurements indicate that the sticking probablility for O2 on a graphite surface with predeposited K is approximately independent on K coverage for coverages down to 0.5 × 1014 cm−2, corresponding to an effective radius of K of ∼ 7.3 Å.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 111: Symposium O – Microstructure and Properties of Catalysts , 1987 , 447
Copyright
Copyright © Materials Research Society 1988

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References

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