Abstract
CO adsorption on the Pt(111) surface is studied using first-principles
methods. As found in a recent study Feibelman et al., J. Phys. Chem.
B 105, 4018 (2001), we find the preferred adsorption site within
density functional theory to be the hollow site, whereas experimentally
it is found that the top site is preferred. The influence of pseudopotential
and exchange-correlation functional error on the CO binding energy
and site preference is carefully investigated. We also compare the
site preference energy of CO on Pt(111) with the reaction energy
of formaldehyde formation from H2 and CO. We show that the discrepancies
between the experimental and theoretical results are due to the generalized
gradient approximation (GGA) treating different bond orders with
varying accuracy. We can therefore expect that GGA results will contain
significant error whenever bonds of different bond order are broken
and formed.
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