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

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

by L. M. Molina and B. Hammer

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

Abstract

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.O₂, 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.