Carbon-carbon coupling of methyl groups on Pt(111)

D. Howard Fairbrother, X. D. Peng, R. Viswanathan, Peter C Stair, M. Trenary, J. Fan

Research output: Contribution to journalArticle

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Abstract

Although methyl radicals are widely postulated to be important intermediates in many catalytic processes involving hydrocarbon species, relatively little is known about their reaction kinetics on metal surfaces. In order to more fully understand the surface chemistry of methyl groups we have developed a source of gas-phase methyl radicals based on the pyrolysis of azomethane. The surface chemistry of methyl groups adsorbed on Pt(111) has been studied using TPD and reflection-absorption infrared spectroscopy (RAIRS). Methyl radicals can be dosed directly onto the surface at 150 K and are bound in a C3v geometry. Methyl groups become thermally activated above 230 K, reacting to produce a hydrogenation product (methane) and various dehydrogenation products. The nature of these dehydrogenation products depends upon the initial methyl coverage. At low coverages CHx (x<3) species are predominant while at higher methyl coverages there is evidence of carbon-carbon coupling reactions to produce higher order hydrocarbons one of which has been identified as ethylidyne (CCH3). Ethylidyne is also observed as a reaction product on Pt(111), at 150 K, for large methyl radical exposures.

Original languageEnglish
JournalSurface Science
Volume285
Issue number1-2
DOIs
Publication statusPublished - Apr 1 1993

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Dehydrogenation
Surface chemistry
Carbon
Hydrocarbons
carbon
Temperature programmed desorption
dehydrogenation
Absorption spectroscopy
Reaction products
Reaction kinetics
Hydrogenation
Infrared spectroscopy
Methane
Pyrolysis
products
hydrocarbons
chemistry
Geometry
Metals
Gases

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Fairbrother, D. H., Peng, X. D., Viswanathan, R., Stair, P. C., Trenary, M., & Fan, J. (1993). Carbon-carbon coupling of methyl groups on Pt(111). Surface Science, 285(1-2). https://doi.org/10.1016/0039-6028(93)90900-5

Carbon-carbon coupling of methyl groups on Pt(111). / Fairbrother, D. Howard; Peng, X. D.; Viswanathan, R.; Stair, Peter C; Trenary, M.; Fan, J.

In: Surface Science, Vol. 285, No. 1-2, 01.04.1993.

Research output: Contribution to journalArticle

Fairbrother, DH, Peng, XD, Viswanathan, R, Stair, PC, Trenary, M & Fan, J 1993, 'Carbon-carbon coupling of methyl groups on Pt(111)', Surface Science, vol. 285, no. 1-2. https://doi.org/10.1016/0039-6028(93)90900-5
Fairbrother DH, Peng XD, Viswanathan R, Stair PC, Trenary M, Fan J. Carbon-carbon coupling of methyl groups on Pt(111). Surface Science. 1993 Apr 1;285(1-2). https://doi.org/10.1016/0039-6028(93)90900-5
Fairbrother, D. Howard ; Peng, X. D. ; Viswanathan, R. ; Stair, Peter C ; Trenary, M. ; Fan, J. / Carbon-carbon coupling of methyl groups on Pt(111). In: Surface Science. 1993 ; Vol. 285, No. 1-2.
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