The adsorption and surface reactions of allyl iodide on the Mo2C/Mo(100) surface

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Abstract

The adsorption and surface reactions of allyl iodide on Mo2C/Mo(100) surface have been investigated by thermal desorption spectroscopy, X-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy (HREELS) in the 100-1200 K temperature range. Allyl iodide adsorbed dissociatively and molecularly on the clean Mo2C/Mo(100) surface at 100 K and desorbed in two TPD peaks at 160 and 180 K, characteristic of condensed and chemisorbed layers, respectively. The rupture of C-I bond in the molecularly adsorbed C3H5I started at 100 K, and was completed at 220 K. C3H5 fragments formed underwent hydrogenation to propene and to propane. Propane desorbed with a Tp=280-300 K and propene with 400-420 K. The desorption of iodine occurred at high temperature with a Tp∼950 K. Analysis of HREELS spectra of the annealed layer suggests the formation of η1-allyl and η3-allyl groups between 100 and 220 K and the presence of di-σ bonded propene at 250-410 K. The latter species underwent dehydrogenation to propylidyne on the one hand, which was identified at 300-400 K on the surface, and was hydrogenated to propyl groups on the other hand. Propylidyne decomposes at higher temperatures leaving carbon on the surface and releasing hydrogen into the gas phase with Tp∼580 K. When the adsorption temperature was 300 K, the accumulation of propylidyne species was facilitated. Illumination of the adsorbed layer at 100 K enhanced the dissociation of allyl iodide. Allyl species formed in higher concentration coupled into hexadiene (Tp=172 K) and hexane (Tp=230 and 325 K).

Original languageEnglish
Pages (from-to)139-149
Number of pages11
JournalSurface Science
Volume519
Issue number1-2
DOIs
Publication statusPublished - Nov 1 2002

Fingerprint

Surface reactions
Iodides
iodides
surface reactions
Propylene
Adsorption
Propane
adsorption
Electron energy loss spectroscopy
propane
energy dissipation
desorption
hexadiene
electron energy
Thermal desorption spectroscopy
spectroscopy
Temperature
high resolution
releasing
Hexanes

Keywords

  • Aromatics
  • Chemisorption
  • Electron energy loss spectroscopy (EELS)
  • Molybdenum
  • Thermal desorption spectroscopy
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

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

Cite this

The adsorption and surface reactions of allyl iodide on the Mo2C/Mo(100) surface. / Bugyi, L.; Oszkó, A.; Solymosi, F.

In: Surface Science, Vol. 519, No. 1-2, 01.11.2002, p. 139-149.

Research output: Contribution to journalArticle

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title = "The adsorption and surface reactions of allyl iodide on the Mo2C/Mo(100) surface",
abstract = "The adsorption and surface reactions of allyl iodide on Mo2C/Mo(100) surface have been investigated by thermal desorption spectroscopy, X-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy (HREELS) in the 100-1200 K temperature range. Allyl iodide adsorbed dissociatively and molecularly on the clean Mo2C/Mo(100) surface at 100 K and desorbed in two TPD peaks at 160 and 180 K, characteristic of condensed and chemisorbed layers, respectively. The rupture of C-I bond in the molecularly adsorbed C3H5I started at 100 K, and was completed at 220 K. C3H5 fragments formed underwent hydrogenation to propene and to propane. Propane desorbed with a Tp=280-300 K and propene with 400-420 K. The desorption of iodine occurred at high temperature with a Tp∼950 K. Analysis of HREELS spectra of the annealed layer suggests the formation of η1-allyl and η3-allyl groups between 100 and 220 K and the presence of di-σ bonded propene at 250-410 K. The latter species underwent dehydrogenation to propylidyne on the one hand, which was identified at 300-400 K on the surface, and was hydrogenated to propyl groups on the other hand. Propylidyne decomposes at higher temperatures leaving carbon on the surface and releasing hydrogen into the gas phase with Tp∼580 K. When the adsorption temperature was 300 K, the accumulation of propylidyne species was facilitated. Illumination of the adsorbed layer at 100 K enhanced the dissociation of allyl iodide. Allyl species formed in higher concentration coupled into hexadiene (Tp=172 K) and hexane (Tp=230 and 325 K).",
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T1 - The adsorption and surface reactions of allyl iodide on the Mo2C/Mo(100) surface

AU - Bugyi, L.

AU - Oszkó, A.

AU - Solymosi, F.

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N2 - The adsorption and surface reactions of allyl iodide on Mo2C/Mo(100) surface have been investigated by thermal desorption spectroscopy, X-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy (HREELS) in the 100-1200 K temperature range. Allyl iodide adsorbed dissociatively and molecularly on the clean Mo2C/Mo(100) surface at 100 K and desorbed in two TPD peaks at 160 and 180 K, characteristic of condensed and chemisorbed layers, respectively. The rupture of C-I bond in the molecularly adsorbed C3H5I started at 100 K, and was completed at 220 K. C3H5 fragments formed underwent hydrogenation to propene and to propane. Propane desorbed with a Tp=280-300 K and propene with 400-420 K. The desorption of iodine occurred at high temperature with a Tp∼950 K. Analysis of HREELS spectra of the annealed layer suggests the formation of η1-allyl and η3-allyl groups between 100 and 220 K and the presence of di-σ bonded propene at 250-410 K. The latter species underwent dehydrogenation to propylidyne on the one hand, which was identified at 300-400 K on the surface, and was hydrogenated to propyl groups on the other hand. Propylidyne decomposes at higher temperatures leaving carbon on the surface and releasing hydrogen into the gas phase with Tp∼580 K. When the adsorption temperature was 300 K, the accumulation of propylidyne species was facilitated. Illumination of the adsorbed layer at 100 K enhanced the dissociation of allyl iodide. Allyl species formed in higher concentration coupled into hexadiene (Tp=172 K) and hexane (Tp=230 and 325 K).

AB - The adsorption and surface reactions of allyl iodide on Mo2C/Mo(100) surface have been investigated by thermal desorption spectroscopy, X-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy (HREELS) in the 100-1200 K temperature range. Allyl iodide adsorbed dissociatively and molecularly on the clean Mo2C/Mo(100) surface at 100 K and desorbed in two TPD peaks at 160 and 180 K, characteristic of condensed and chemisorbed layers, respectively. The rupture of C-I bond in the molecularly adsorbed C3H5I started at 100 K, and was completed at 220 K. C3H5 fragments formed underwent hydrogenation to propene and to propane. Propane desorbed with a Tp=280-300 K and propene with 400-420 K. The desorption of iodine occurred at high temperature with a Tp∼950 K. Analysis of HREELS spectra of the annealed layer suggests the formation of η1-allyl and η3-allyl groups between 100 and 220 K and the presence of di-σ bonded propene at 250-410 K. The latter species underwent dehydrogenation to propylidyne on the one hand, which was identified at 300-400 K on the surface, and was hydrogenated to propyl groups on the other hand. Propylidyne decomposes at higher temperatures leaving carbon on the surface and releasing hydrogen into the gas phase with Tp∼580 K. When the adsorption temperature was 300 K, the accumulation of propylidyne species was facilitated. Illumination of the adsorbed layer at 100 K enhanced the dissociation of allyl iodide. Allyl species formed in higher concentration coupled into hexadiene (Tp=172 K) and hexane (Tp=230 and 325 K).

KW - Aromatics

KW - Chemisorption

KW - Electron energy loss spectroscopy (EELS)

KW - Molybdenum

KW - Thermal desorption spectroscopy

KW - X-ray photoelectron spectroscopy

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