skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Molecular modeling of ethylidyne adsorption and diffusion on Pt(111)

Abstract

The adsorption geometry and diffusion behavior of ethylidyne (CCH{sub 3}) on Pt(111) is studied in order to help elucidate the role of this hydrocarbon species during ethylene hydrogenation and dehydrogenation over Pt catalysts. A variant of the extended Hueckel method is used, which allows bond-specific parametrization in molecules. It is adapted to geometrically infinite periodic systems, and empirical parameter values suitable for hydrocarbons on Pt surfaces are developed. The 3-fold fcc and hcp hollows are found to be the most stable adsorption sites, with an energy barrier of about 0.11 eV between them. This barrier suggests relatively easy diffusion of ethylidyne along the Pt(111) surface (subject only to steric intermolecular constraints), allowing unimpeded ethylene approach by opening up sites where subsequent hydrogenation reactions could take place with preadsorbed hydrogen. 30 refs., 3 figs., 3 tabs.

Authors:
; ;  [1]
  1. Lawrence Berkeley Lab., CA (United States)
Publication Date:
OSTI Identifier:
249645
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Other Information: PBD: 6 Mar 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 66 PHYSICS; 36 MATERIALS SCIENCE; HYDROCARBONS; ADSORPTION; DIFFUSION; ETHYLENE; HYDROGENATION; DEHYDROGENATION; PLATINUM; MOLECULAR MODELS; POTENTIAL ENERGY; DIFFUSION BARRIERS

Citation Formats

Nomikou, Z, Van Hove, M A, Somorjai, G A, and Univ. of California, Berkeley, CA. Molecular modeling of ethylidyne adsorption and diffusion on Pt(111). United States: N. p., 1996. Web. doi:10.1021/la9503921.
Nomikou, Z, Van Hove, M A, Somorjai, G A, & Univ. of California, Berkeley, CA. Molecular modeling of ethylidyne adsorption and diffusion on Pt(111). United States. doi:10.1021/la9503921.
Nomikou, Z, Van Hove, M A, Somorjai, G A, and Univ. of California, Berkeley, CA. Wed . "Molecular modeling of ethylidyne adsorption and diffusion on Pt(111)". United States. doi:10.1021/la9503921.
@article{osti_249645,
title = {Molecular modeling of ethylidyne adsorption and diffusion on Pt(111)},
author = {Nomikou, Z and Van Hove, M A and Somorjai, G A and Univ. of California, Berkeley, CA},
abstractNote = {The adsorption geometry and diffusion behavior of ethylidyne (CCH{sub 3}) on Pt(111) is studied in order to help elucidate the role of this hydrocarbon species during ethylene hydrogenation and dehydrogenation over Pt catalysts. A variant of the extended Hueckel method is used, which allows bond-specific parametrization in molecules. It is adapted to geometrically infinite periodic systems, and empirical parameter values suitable for hydrocarbons on Pt surfaces are developed. The 3-fold fcc and hcp hollows are found to be the most stable adsorption sites, with an energy barrier of about 0.11 eV between them. This barrier suggests relatively easy diffusion of ethylidyne along the Pt(111) surface (subject only to steric intermolecular constraints), allowing unimpeded ethylene approach by opening up sites where subsequent hydrogenation reactions could take place with preadsorbed hydrogen. 30 refs., 3 figs., 3 tabs.},
doi = {10.1021/la9503921},
journal = {Langmuir},
number = 5,
volume = 12,
place = {United States},
year = {1996},
month = {3}
}