The adsorption and surface chemistry CH{sub 3} on Pt(111)

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:141424

Fairbrother, D H; Peng, X D; Stair, P C ^[1]; Fan, J; Trenary, M ^[2]

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1. Northwestern Univ., Evanston, IL (United States)
2. Univ. of Illinois, Chicago, IL (United States)

The adsorption and surface chemistry of methyl radicals on Pt(111) has been studied by temperature programmed desorption (TPD), reflection-adsorption infrared reflection spectroscopy (RAIRS), and isotopic tracer experiments. Methyl radicals were introduced on the surface directly from the gas using a methyl radical source based on the pyrolysis of azomethane, CH{sub 3}NNCH{sub 3}. Methyl radicals adsorb with near-unity sticking probability on clean Pt(111) at 150 K to form surface methyl groups detectable by RAIRS. Between 180 K and 300 K the methyl groups react with surface hydrogen to form CH{sub 4} which desorbs from the surface. The hydrogen is derived from adsorption of H{sub 2} and dehydrogenation of adsorbed CH{sub 3}. At high methyl coverages C-C bond formation is observed which leads to the production of surface ethylidyne, {triple_bond}C-CH{sub 3}. Kinetic modeling of the surface reaction will be discussed.

• OSTI ID: 141424
• Report Number(s): CONF-930304--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ADSORPTION
CHEMICAL REACTIONS
METHYL RADICALS
PLATINUM
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE RANGE 0065-0273 K