Surface reactivity enhancement by O dissociation on a single-layer MgO film deposited on metal substrate.

Improving reactivity on an insulating surface is crucial due to its important applications in surface catalytic reactions. In this work, we carried out first-principles calculations to investigate the adsorption of O on a single-layer MgO(100) film deposited on a metal substrate. The adsorption configurations, reaction pathways, molecular dynamics simulations, and electronic properties are reported. We reveal that O can completely dissociate on the surface, which is in sharp contrast to that on MgO(100) films thicker than one monolayer. The dissociated O tends to penetrate into the interfacial region, behaving like a switch to trigger subsequent chemical reactions. As an example, the interplay between water and the interfacial oxygen results in the formation of hydroxyl radicals. This study paves an avenue to accomplish the desired surface catalytic reactions, especially those involving oxygen.