First-principles study of adsorption of methyl, coadsorption of methyl and hydrogen, and methane dissociation on Ni(100)

The adsorption of methyl on Ni(100) has been investigated using density functional theory calculations based on plane-wave expansion and pseudo-potential treatment. It was found that the bridge site with one of the hydrogen atoms near top site is most favorable. The calculated C-H symmetric stretching frequencies for the preferred bridge site showed a significant mode softening, thanks to the three-center bonding between C-H and Ni. The coadsorption of methyl and hydrogen on Ni(100) has also been calculated. The methyl at a bridge site with coadsorbed hydrogen at a hollow site was found to be preferred. In addition, the dissociation of methane on Ni(100) has been studied and the barrier height was found to be 0.73 eV, in good agreement with the recent experimental value of 0.61 eV. (c) 2005 Elsevier B.V. All rights reserved.