Hydrogen atom reactions with monolayer graphite edges on Pt(100) surfaces: hydrogenation and H abstraction
| Autor: | Jürgen Küppers, A. Horn, J. Biener, Th. Zecho |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Hydrogen
Thermal desorption spectroscopy Electron energy loss spectroscopy Analytical chemistry chemistry.chemical_element Surfaces and Interfaces Hydrogen atom Condensed Matter Physics Surfaces Coatings and Films Crystallography chemistry Chemisorption Monolayer Materials Chemistry Graphite Platinum |
| Zdroj: | Surface Science. 397:108-115 |
| ISSN: | 0039-6028 |
| Popis: | The interaction of thermal H (D) atoms with monolayers of graphite deposited on Pt(100) surfaces was studied with LEED, AES, TDS and HREELS. H (D) atoms react with C atoms at the zigzag and armchair edges of C islands via the formation of sp 3 CH (CD) and CH 2 (CD 2 ) edge groups. The initial transformation C→CH (CD) occurs with a constant probability via a precursor state which is restricted to the immediate vicinity of the edges. The hydrogenation of monohydride CH (CD) groups to dihydride CH 2 (CD 2 ) occurs with a cross-section of about 1.5 A 2 . The abstraction reactions of H (D) from monohydride and dihydride groups by H or D via H 2 (D 2 ) formation have cross-sections of 0.1 and 1 A 2 , respectively. The magnitude of these cross-sections are expected for direct Eley-Rideal-type reactions. Isotope exchange reactions were measured by subjecting dihydride CD 2 (CH 2 ) groups to fluences of H (D) atoms. The observed cross-sections suggest a direct exchange via H + CD 2 →CDH + D. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect