Interaction of water and carbon monoxide with MnO(001) thin films on Au(111)

Abstract

Atomically defined MnO(001) thin films were grown on an Au(111) substrate, and their interaction with water (D₂O) was investigated by infrared reflection absorption spectroscopy (IRAS) and thermal desorption spectroscopy (TDS). Carbon monoxide adsorption experiments were performed to probe surface atoms and defects on oxide films. Next, water interaction was investigated from which an associative binding pathway and a dissociative binding pathway were revealed, where the water molecules adsorb at terraces and water dissociation takes place at oxygen vacancies mediated by nearby Mn²⁺ sites. The IRAS data are supported by TDS experiments, which also manifest the importance of defects in the adsorption characteristics of MnO.