Relationship of bond strengths to selectivity in heterogeneous surface reactions: Mercaptoethanol and ethanedithiol on Ni(110)

Journal Article · Thu Aug 24 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100034a033· OSTI ID:219679

Huntley, D R ^[1]

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1. Oak Ridge National Lab., TN (United States)

The reaction selectivities and bonding configurations in mercaptoethanol (HSCH{sub 2}CH{sub 2}OH) and ethanedithiol (HSCH{sub 2}CH{sub 2}SH) on Ni(110) were determined and found to be correlated to the relative strengths of the C-S and C-O bonds. Mechanistic details of the mercaptoethanol reaction have been elucidated. Mercaptoethanol reacts with Ni(110) to form ethanol, acetaldehyde, methane, CO, and hydrogen. Mercaptoethanol reactivity is dominated by thiolate formation as suggested by the S 2p core level binding energy. Near 200-250K, the C-S bond cleaves with the evolution of ethanol and formation of surface ethoxide which is easily discernible from vibrational spectroscopy. The ethoxide dehydrogenates to form acetaldehyde, which either desorbs or reacts to form methane and CO. In dramatic contrast, the structurally similar ethanedithiol apparently adsorbs in a bidentate fashion, resulting in a dithiolate which selectively splits out thylene and produces surface sulfur. The difference in the reactivity of ethanedithiol and mercaptoethanol is understood in terms of the inactivity of the Ni(110) surface toward C-O bond scission, which is primarily a reflection of the strength of C-O bonds compared with C-S bonds. 35 refs., 8 figs., 2 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 219679
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 34 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ACETALDEHYDE
ACTIVATION ENERGY
ADSORPTION
BINDING ENERGY
CARBON MONOXIDE
CHEMICAL BONDS
CHEMICAL REACTIONS
CLEAVAGE
DESORPTION
ENERGY SPECTRA
ETHANOL
METHANE
MONOCRYSTALS
NICKEL
ORGANIC SULFUR COMPOUNDS
THIOLS