Active role of oxide support during CO oxidation at Au/MgO.

Active role of oxide support during CO oxidation at Au/MgO.
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by L. M. Molina and B. Hammer

Phys. Rev. Lett. **90**, 206102 (2003).

Abstract
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The oxidation of CO at MgO supported gold aggregates is studied by means
of density functional theory calculations. In addition to serving as a
structural promoter holding the gold particles, the supporting oxide
also takes an active role in the bonding and activation of adsorbates
bound to the gold. The oxide stabilizes a peroxolike reaction
intermediate, CO.O\ :sub:`2`, and causes steric repulsion to CO. The
most reactive site at Au/MgO appears where the gold shelters the MgO
thereby creating a cavity where several low-coordinated Au atoms and
Mg2+ cations from the substrate can interact simultaneously with an
adsorbate.