O2 activation at the Au/MgO(001) interface boundary facilitates CO oxidation

Abstract

Density functional theory calculations reveal that the work function of Au supported on MgO(001) is substantially reduced because of an interfacial dipole moment formed at the Au/MgO interface. Consequently, the Au/MgO interface plays an active role in the activation of O₂ molecules by promoting charge transfer to the O₂ 2π* orbital. The presence of F-centers in the MgO substrate can further promote the charge transfer and bonding of O₂ at the interface boundary. However, O₂ dissociation is kinetically hindered. The system is then able to catalyze CO oxidation at low temperature as adsorbed CO and O₂ readily react to form CO₂ with a low energy barrier.