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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

[1] For reviews see McKee, D.W., Chem. Phys. Carbon 16, 1 (1981); B. Wood and K.M. Sancier, Cat. Rev. Sci. Eng. 26, 233 (1984).Google Scholar
[2] Fuel vol.62 (1983) and Fuel vol.65 (1986) contain the papers presented at the “International Symposia on the Fundamentals of Catalytic Coal and Carbon Gasification”, in the Netherlands, in 1982 and 1986.Google Scholar
[3] Kelemen, S.R. and Freund, H., J. Catal. 102, 80 (1986).Google Scholar
[4] Mims, C.A., Chludzinski, J.J. Jr., Pabst, J.K. and Baker, R.T.K., J. Catal. 8, 97 (1984).Google Scholar
[5] Mims, C.A. and Pabst, J.K., J. Catal. 107, 209 (1987).Google Scholar
[6] Cerfontain, M.B., Meijer, R., Kapteijn, F. and Moulijn, J.A., J. Catal. 107, 173 (1987).CrossRefGoogle Scholar
[7] Cabrera, A.L., Heinemann, H. and Somorjai, G.A., J. Catal. 25, 7 (1982).Google Scholar
[8] Johnson, M.T., Starnberg, H.I. and Hughes, H.P., Surf, Sci. 178, 290 (1986).Google Scholar
[9] Barber, M., Evans, E.L. and Thomas, J.M., Chem. Phys. Lett. 18, 423 (1973).Google Scholar
[10] Kelemen, S.R., Freund, H. and Mims, C.A., J. Vac. Sci. Technol. A2, 987 (1984).Google Scholar
[11] Kelemen, S.R. and Mims, C.A., Surf. Sci. 133, 71 (1983).Google Scholar
[12] Kelemen, S.R., Freund, H. and Mims, C.A., J. Catal. 27, 228 (1986).Google Scholar
[13] Bonzel, H.P., Surf. Sci. Rept. 8, 43 (1987).Google Scholar
[14] Sumev, L., Rangelov, G. and Kiskinova, M., Surf. Sci. 179, 283 (1987).Google Scholar
[15] Pirug, G., Brodén, G. and Bonzel, H.P., Surf. Sci. 94, 323 (1980).Google Scholar
[16] Whitman, L.J., Bartosch, C.E. and Ho, W., J. Chem. Phys. 85, 3688 (1986).Google Scholar
[17] Bugyi, L. and Solymosi, F., Surf. Sci. 188, 475 (1987).CrossRefGoogle Scholar
[18] Solymosi, F. and Berkó, A., J. Catal. 101, 458 (1986).Google Scholar
[19] Nørskov, J.K., Holloway, S. and Lang, N.D., Surf. Sci. 137, 65 (1984).Google Scholar
[20] Lang, N.D., Holloway, S. and Nørskov, J.K., Surf. Sci. 150, 24 (1985).CrossRefGoogle Scholar
[21] Feibelman, P.J. and Hamann, D.R., Surf. Sci. 149, 48 (1985).Google Scholar
[22] Keck, K.-E., Kasemo, B. and Högberg, T., Surf. Sci. 126, 469 (1983).CrossRefGoogle Scholar
[23] Sjövall, P., Hellsing, B., Keck, K.-E. and Kasemo, B., J. Vac. Sci. Technol. A 5, 1065 (1987).Google Scholar
[24] Wicke, B.G., Wong, Chor and Grady, K.A., Combust. Flame 66, 37 (1987).Google Scholar
[25] ΔE is estimated from the desorption temperature Td = 65 K in a phase diagram of O2 on graphite in Stephens, P.W., Heiney, P.A., Birgenean, R.J., Horn, P.M., Stottenberg, J. and Vilches, O.E., Phys. Rev. Lett. 45, 1959 (1980). This gives ΔE = −0.18 eV.CrossRefGoogle Scholar