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A theoretical study of CH4 dissociation on pure and gold-alloyed Ni(111) surfaces.

Authors :
Kratzer, P.
Hammer, B.
No\rskov, J. K.
Source :
Journal of Chemical Physics; 10/1/1996, Vol. 105 Issue 13, p5595, 10p
Publication Year :
1996

Abstract

We present a density functional theory study of the first step of CH4 adsorption on the Ni(111) surface, dissociation into adsorbed CH3 and H. The rupture of the C–H bond occurs preferentially on top of a Ni atom, with a dissociation barrier of about 100 kJ/mol (including zero point corrections). The transition state involves considerable internal excitation of the molecule. The active C–H bond is both stretched to 1.6 Å and tilted relative to the methyl group. A normal mode analysis shows that the reaction coordinate is mainly a C–H stretch, while the orientation of the C–H bond relative to the surface is responsible for the highest real mode. Alloying the surface with gold also affects the reactivity of the Ni atoms on adjacent surface sites. The dissociation barrier is increased by 16 and 38 kJ/mol for a Ni atom with one or two gold neighbors, respectively. We attribute these changes to a shift in the local density of d states at the nickel atoms in the neighborhood of gold. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
105
Issue :
13
Database :
Complementary Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
7647624
Full Text :
https://doi.org/10.1063/1.472399