A Feature of the MgO(111) Surface As a Substrate for Deposited Nanosized Au Particles in the Adsorption and Interaction of CO, NO, and O-2 Molecules

摘要

A set of ultrahigh-vacuum surface analysis techniques are used to make a comparative study of the formation of nanosized gold clusters on the surfaces of MgO(111) films on the one hand, and MgO(100) films on the other, along with the adsorption and interaction of CO, NO, and O-2 molecules on the surfaces of the corresponding metal oxide systems Au/MgO(111) and Au/MgO(100). It is shown that gold particles 2-3 nm in size, deposited on the surface of a MgO(111) film, acquire an effective positive charge as a result of the electron density transfer toward the substrate to stabilize the uncompensated for dipole moment of the polar MgO(111) surface. The state of this metal oxide system manifests in more efficient oxidation of CO molecules by both oxygen and coadsorbed NO molecules, relative to a system based on the nonpolar MgO(100) surface.