First-Principles Simulations of H2O Dissociation at the Interfacial Region Formed by a Molybdenum Oxide Cluster and a Reduced MoO3–x Surface

Water dissociation is a key elementary step in many important surface and catalytic processes. For the adsorption and dissociation of H2O molecules, oxygen defects on oxide surfaces usually play an essential role. Here, using density functional theory calculations combined with ab initio molecular dynamics simulations, we propose an interfacial model system where a molybdenum oxide cluster is supported on a reduced MoO3–x surface and investigate the adsorption and dissociation of H2O at the interface. It is found that the exposed Mo atoms near oxygen vacancy sites and neighboring oxygen species together create a favorable microscopic environment for the adsorption and dissociation of H2O molecules, resulting in a low dissociation barrier. The above processes are not hindered by the coexistence of CO. This work provides an understanding of H2O dissociation on irregular oxide systems and may aid in the design of relevant catalysts.