Abstract
The CO/H coadsorption on the Ni(100) surface is discussed in this study. Relative stabilities of various possible surface structures are compared for the initial state (lower temperature form), as well as the final state (higher temperature form) of the coadsorption system. The surface-adsorbate bonding in the Ni(100)/H(4)/CO(t) structure (H(4) stands for hydrogen atoms adsorbed in a 4-fold hollow site and CO(t) stands for carbon monoxide in the on-top position), the most favorable choice of the lower temperature state, resembles that of the singly adsorbed systems. The adsorbate-adsorbate interaction does not lead to any chemical bonds but does affect the surface-CO π bonding. Destabilization of the CO 2π orbitale due to the 2π-1s(H) interaction results in a depopulation of the 2π states and a strengthening of the C-O bond. For the observed higher temperature c(2√2×√2)R45° geometry of CO, possible H and H2 (adsorbed hydrogen molecule) arrangements in the final surface state are compared. Energy and crystal overlap population analyses show that the 4-fold adsorption site for both H and H2 gives good agreement with the experimental observations. A new adsorbate-adsorbate coupling between CO(t) and H2(4) (hydrogen molecule adsorbed in a 4-fold hollow site) is seen, but this coupling does not significantly affect the surface-adsorbate bonding. Again, no C-H or O-H bonds are formed. Besides the favorable CO(t)/CO(4) (half of the CO's adsorbed terminally and the other half in the 4-fold hollow site) configuration, our calculations also reveal the possibility of a CO(t)/CO(b) combination (half of the CO's adsorbed terminally and the other half in a bridging manner) in the final state.
| Original language | English |
|---|---|
| Pages (from-to) | 1554-1564 |
| Number of pages | 11 |
| Journal | Journal of Physical Chemistry |
| Volume | 94 |
| Issue number | 4 |
| Publication status | Published - 1990 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
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Coadsorption of carbon monoxide and hydrogen on the Ni(100) surface : A theoretical investigation of site preferences and surface bonding. / Li, Jing; Schiøtt, Birgit; Hoffmann, Roald; Proserpio, Davide M.
In: Journal of Physical Chemistry, Vol. 94, No. 4, 1990, p. 1554-1564.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Coadsorption of carbon monoxide and hydrogen on the Ni(100) surface
T2 - A theoretical investigation of site preferences and surface bonding
AU - Li, Jing
AU - Schiøtt, Birgit
AU - Hoffmann, Roald
AU - Proserpio, Davide M.
PY - 1990
Y1 - 1990
N2 - The CO/H coadsorption on the Ni(100) surface is discussed in this study. Relative stabilities of various possible surface structures are compared for the initial state (lower temperature form), as well as the final state (higher temperature form) of the coadsorption system. The surface-adsorbate bonding in the Ni(100)/H(4)/CO(t) structure (H(4) stands for hydrogen atoms adsorbed in a 4-fold hollow site and CO(t) stands for carbon monoxide in the on-top position), the most favorable choice of the lower temperature state, resembles that of the singly adsorbed systems. The adsorbate-adsorbate interaction does not lead to any chemical bonds but does affect the surface-CO π bonding. Destabilization of the CO 2π orbitale due to the 2π-1s(H) interaction results in a depopulation of the 2π states and a strengthening of the C-O bond. For the observed higher temperature c(2√2×√2)R45° geometry of CO, possible H and H2 (adsorbed hydrogen molecule) arrangements in the final surface state are compared. Energy and crystal overlap population analyses show that the 4-fold adsorption site for both H and H2 gives good agreement with the experimental observations. A new adsorbate-adsorbate coupling between CO(t) and H2(4) (hydrogen molecule adsorbed in a 4-fold hollow site) is seen, but this coupling does not significantly affect the surface-adsorbate bonding. Again, no C-H or O-H bonds are formed. Besides the favorable CO(t)/CO(4) (half of the CO's adsorbed terminally and the other half in the 4-fold hollow site) configuration, our calculations also reveal the possibility of a CO(t)/CO(b) combination (half of the CO's adsorbed terminally and the other half in a bridging manner) in the final state.
AB - The CO/H coadsorption on the Ni(100) surface is discussed in this study. Relative stabilities of various possible surface structures are compared for the initial state (lower temperature form), as well as the final state (higher temperature form) of the coadsorption system. The surface-adsorbate bonding in the Ni(100)/H(4)/CO(t) structure (H(4) stands for hydrogen atoms adsorbed in a 4-fold hollow site and CO(t) stands for carbon monoxide in the on-top position), the most favorable choice of the lower temperature state, resembles that of the singly adsorbed systems. The adsorbate-adsorbate interaction does not lead to any chemical bonds but does affect the surface-CO π bonding. Destabilization of the CO 2π orbitale due to the 2π-1s(H) interaction results in a depopulation of the 2π states and a strengthening of the C-O bond. For the observed higher temperature c(2√2×√2)R45° geometry of CO, possible H and H2 (adsorbed hydrogen molecule) arrangements in the final surface state are compared. Energy and crystal overlap population analyses show that the 4-fold adsorption site for both H and H2 gives good agreement with the experimental observations. A new adsorbate-adsorbate coupling between CO(t) and H2(4) (hydrogen molecule adsorbed in a 4-fold hollow site) is seen, but this coupling does not significantly affect the surface-adsorbate bonding. Again, no C-H or O-H bonds are formed. Besides the favorable CO(t)/CO(4) (half of the CO's adsorbed terminally and the other half in the 4-fold hollow site) configuration, our calculations also reveal the possibility of a CO(t)/CO(b) combination (half of the CO's adsorbed terminally and the other half in a bridging manner) in the final state.
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M3 - Article
VL - 94
SP - 1554
EP - 1564
JO - Journal of Physical Chemistry
JF - Journal of Physical Chemistry
SN - 0022-3654
IS - 4
ER -