Generation of CH2 species

thermal and photo-induced dissociation of CH2I2 on Rh(111) surface

G. Klivényi, F. Solymosi

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

The thermal and photochemistry of methylene iodide, CH2I2, on Rh(111) surface has been investigated by high resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron (XPS), Auger electron (AES) and temperature programmed desorption (TPD) spectroscopies. CH2I2 adsorbs dissociatively at submonolayer coverage at 90 K and molecularly at higher coverages. The dissociation of a monolayer starts above 170 K and completes below 250 K. Illumination of adsorbed CH2I2 enhanced the extent of the dissociation which is ascribed to the generation of photoelectrons. The primary products of thermal dissociation is adsorbed CH2 and I. The species CH2 is stable on Rh(111) surface up to 300 K: its larger fraction undergoes self-hydrogenation to CH4 at 200-300 K, and a much smaller fraction dimerizes into C2H4. Coadsorbed O atoms inhibited the C-I bond breaking and, in addition, reacted with adsorbed CH2 to give formaldehyde at 170-340 K, and CO2 and H2O at 340-460 K. No couplings between CH2 and CH3, and CH2 and C2H5 have been observed.

Original languageEnglish
Pages (from-to)168-184
Number of pages17
JournalSurface Science
Volume342
Issue number1-3
DOIs
Publication statusPublished - Nov 20 1995

Fingerprint

photoelectrons
dissociation
Photoelectrons
thermal dissociation
formaldehyde
methylene
photochemical reactions
iodides
spectroscopy
hydrogenation
energy dissipation
Photochemical reactions
Electron energy loss spectroscopy
desorption
illumination
electron energy
Temperature programmed desorption
Formaldehyde
Hydrogenation
Monolayers

Keywords

  • Alkene halide
  • Electron energy loss spectroscopy
  • Low index single crystal surfaces
  • Photochemistry
  • Rhodium
  • Solid-gas interfaces
  • Surface chemical reaction

ASJC Scopus subject areas

  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry

Cite this

Generation of CH2 species : thermal and photo-induced dissociation of CH2I2 on Rh(111) surface. / Klivényi, G.; Solymosi, F.

In: Surface Science, Vol. 342, No. 1-3, 20.11.1995, p. 168-184.

Research output: Contribution to journalArticle

@article{92fc694ad7d0421fb416d275f2785654,
title = "Generation of CH2 species: thermal and photo-induced dissociation of CH2I2 on Rh(111) surface",
abstract = "The thermal and photochemistry of methylene iodide, CH2I2, on Rh(111) surface has been investigated by high resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron (XPS), Auger electron (AES) and temperature programmed desorption (TPD) spectroscopies. CH2I2 adsorbs dissociatively at submonolayer coverage at 90 K and molecularly at higher coverages. The dissociation of a monolayer starts above 170 K and completes below 250 K. Illumination of adsorbed CH2I2 enhanced the extent of the dissociation which is ascribed to the generation of photoelectrons. The primary products of thermal dissociation is adsorbed CH2 and I. The species CH2 is stable on Rh(111) surface up to 300 K: its larger fraction undergoes self-hydrogenation to CH4 at 200-300 K, and a much smaller fraction dimerizes into C2H4. Coadsorbed O atoms inhibited the C-I bond breaking and, in addition, reacted with adsorbed CH2 to give formaldehyde at 170-340 K, and CO2 and H2O at 340-460 K. No couplings between CH2 and CH3, and CH2 and C2H5 have been observed.",
keywords = "Alkene halide, Electron energy loss spectroscopy, Low index single crystal surfaces, Photochemistry, Rhodium, Solid-gas interfaces, Surface chemical reaction",
author = "G. Kliv{\'e}nyi and F. Solymosi",
year = "1995",
month = "11",
day = "20",
doi = "10.1016/0039-6028(95)00767-9",
language = "English",
volume = "342",
pages = "168--184",
journal = "Surface Science",
issn = "0039-6028",
publisher = "Elsevier",
number = "1-3",

}

TY - JOUR

T1 - Generation of CH2 species

T2 - thermal and photo-induced dissociation of CH2I2 on Rh(111) surface

AU - Klivényi, G.

AU - Solymosi, F.

PY - 1995/11/20

Y1 - 1995/11/20

N2 - The thermal and photochemistry of methylene iodide, CH2I2, on Rh(111) surface has been investigated by high resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron (XPS), Auger electron (AES) and temperature programmed desorption (TPD) spectroscopies. CH2I2 adsorbs dissociatively at submonolayer coverage at 90 K and molecularly at higher coverages. The dissociation of a monolayer starts above 170 K and completes below 250 K. Illumination of adsorbed CH2I2 enhanced the extent of the dissociation which is ascribed to the generation of photoelectrons. The primary products of thermal dissociation is adsorbed CH2 and I. The species CH2 is stable on Rh(111) surface up to 300 K: its larger fraction undergoes self-hydrogenation to CH4 at 200-300 K, and a much smaller fraction dimerizes into C2H4. Coadsorbed O atoms inhibited the C-I bond breaking and, in addition, reacted with adsorbed CH2 to give formaldehyde at 170-340 K, and CO2 and H2O at 340-460 K. No couplings between CH2 and CH3, and CH2 and C2H5 have been observed.

AB - The thermal and photochemistry of methylene iodide, CH2I2, on Rh(111) surface has been investigated by high resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron (XPS), Auger electron (AES) and temperature programmed desorption (TPD) spectroscopies. CH2I2 adsorbs dissociatively at submonolayer coverage at 90 K and molecularly at higher coverages. The dissociation of a monolayer starts above 170 K and completes below 250 K. Illumination of adsorbed CH2I2 enhanced the extent of the dissociation which is ascribed to the generation of photoelectrons. The primary products of thermal dissociation is adsorbed CH2 and I. The species CH2 is stable on Rh(111) surface up to 300 K: its larger fraction undergoes self-hydrogenation to CH4 at 200-300 K, and a much smaller fraction dimerizes into C2H4. Coadsorbed O atoms inhibited the C-I bond breaking and, in addition, reacted with adsorbed CH2 to give formaldehyde at 170-340 K, and CO2 and H2O at 340-460 K. No couplings between CH2 and CH3, and CH2 and C2H5 have been observed.

KW - Alkene halide

KW - Electron energy loss spectroscopy

KW - Low index single crystal surfaces

KW - Photochemistry

KW - Rhodium

KW - Solid-gas interfaces

KW - Surface chemical reaction

UR - http://www.scopus.com/inward/record.url?scp=0029405463&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029405463&partnerID=8YFLogxK

U2 - 10.1016/0039-6028(95)00767-9

DO - 10.1016/0039-6028(95)00767-9

M3 - Article

VL - 342

SP - 168

EP - 184

JO - Surface Science

JF - Surface Science

SN - 0039-6028

IS - 1-3

ER -