Generation of highly reactive oxygen species by co-adsorption of oxygen and water on metal-supported MgO(100) thinfilms

TL;DR

This study uses density-functional theory to show how co-adsorption of oxygen and water on metal-supported MgO(100) thin films can generate highly reactive oxygen species, informing catalyst design.

Contribution

It reveals the mechanisms and pathways for ROS formation on MgO(100) films supported on Mo(100), highlighting the effects of water, substrate, and film thickness.

Findings

Complete decomposition of molecular oxygen assisted by water.

Formation of superoxide, hydroperoxide, hydroxyl, and oxygen adatoms.

Reaction barriers and effects of film thickness analyzed.

Abstract

The formation of highly reactive oxygen species (ROS) on metal oxide surfaces have attracted considerable interest due to their diverse applications. In this work, we have performed densi-ty-functional theory calculations to investigate the co-adsorption of oxygen and water on ul-trathin MgO(100) films deposited on Mo(100) substrate. We reveal that the molecular oxygen can be stepwise decomposed completely with the assistance of water. Consequently, a series of highly ROS including superoxide, hydroperoxide, hydroxyl and single oxygen adatom are formed on Mo(100) supported MgO(100) thinfilms. The reaction barriers accompanied by the generation of ROS are reported, and the influence of the thickness of MgO(100) films is also discussed. The most promising routes to produce these fascinating species provide valuable information to understand the importance of synergistic effect, namely the substrate, the co-adorbed species, and the film thickness, in multiphase catalyst design.