Electronic Structure Studies of the Interaction of Water with a Cu(100) Surface (original) (raw)
2001, American Chemical Society eBooks
The results of a density functional study of the chemisorption of water on a Cu(100) surface are presented. Both atomic cluster and periodic supercell models of the surface were used in the investigation. From the cluster studies a single water molecule is bound by about 0.6 eV to the surface and is in an on-top site. The addition of a second water molecule in a site adjacent to the first one is not favorable due to polarization of the electron density near the surface. The periodic density functional calculations give results consistent with the cluster studies. The nature of the interaction of water with noble metal surfaces is of great importance in electrochemistry, corrosion, and heterogeneous catalysis. There is evidence that intermolecular interactions between water molecules can compete with water-surface interactions, although little is known about the role that hydrogen bonding between water molecules plays in determining the structure of the metal/water interface. Very little is known experimentally about the nature of the interaction of a single water molecule with noble metal surfaces because it is difficult to separate out the water/water effects from the water/surface interactions. In a study of water on a Au(lll) surface, Kay et al.(i) have reported that the temperature programmed desorption (TPD) spectrum does not display a well-resolved submonolayer peak indicating that H 2 0 binds more strongly to itself than to the Au substrate. Arrhenius analysis of the TPD peak gave a binding energy of about 0.4 eV. In an electronenergy-loss spectroscopic (EELS) study of water on a Cu(100) surface , Andersson et al. (2) found that it adsorbs with the oxygen end towards the surface and its molecular axis significantly tilted relative to the surface normal.
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