Reactions of ethanethiol on Mo(110): formation and decomposition of a surface alkyl thiolate

Journal Article · Thu Sep 08 04:00:00 EDT 1988 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100329a029· OSTI ID:5993817

Roberts, J T; Friend, C M

The reactions of ethanethiol (C/sub 2/H/sub 5/SH) on Mo(110) under ultrahigh vacuum have been investigated by temperature-programmed reaction, X-ray photoelectron, and high-resolution electron energy loss spectroscopies. Electron energy loss spectroscopy indicates that the S-H bond in ethanethiol dissociates below 120 K to form a surface ethyl thiolate (C/sub 2/H/sub 5/S). At low coverages the ethyl thiolate decomposes to atomic carbon, atomic sulfur, and gaseous H/sub 2/, with decomposition complete below 350 K. At high coverages, the surface thiolate decomposes during temperature-programmed reaction via three competing pathways: hydrogenolysis at 300 K to gaseous ethane, dehydrogenation at 340 K to gaseous ethylene, and decomposition to surface carbon, surface sulfur, and gaseous dihydrogen. Notably, the presence of surface atomic sulfur is not necessary for selective formation on clean Mo(110); the thiolate remains intact up to the temperature of hydrogenolysis onset. The last pathway proceeds via a hydrocarbon fragment(s) which decomposes at 570 K to gaseous H/sub 2/ and atomic carbon. At saturation, /approximately/ 75% of all irreversibly chemisorbed ethanethiol forms gaseous hydrocarbons. The coverage-dependent kinetics for ethanethiol decomposition are discussed in terms of electronic and site-blocking effects.

• Research Organization: Harvard Univ., Cambridge, MA (USA)
• DOE Contract Number: FG02-84ER13289
• OSTI ID: 5993817
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:18; ISSN JPCHA
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
DATA
DESULFURIZATION
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY-LOSS SPECTROSCOPY
EXPERIMENTAL DATA
INFORMATION
IONIZING RADIATIONS
KINETICS
METALS
MILLER INDICES
MOLYBDENUM
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
RADIATIONS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SPECTROSCOPY
THERMAL ANALYSIS
THIOLS
TRANSITION ELEMENTS
X RADIATION