Interaction of Oxygen with Pristine and Defective MoS2 Monolayers

Atom-controlled sub-nanometer MoS2 pores have been recently designed thanks to precise defect control techniques. This opens the path for several technological applications, such as electronics, sensing, and energy production and storage. Also, it is well known that oxidative environments are of particular interest for these applications. In this work, we carried out first-principles calculations of oxygen adsorption in pristine and sub-nanometer MoS2 nanopores. The chemical stability of the 2 H-MoS2 monolayers and nanopores towards oxygen was verified using density-functional theory and ab initio molecular dynamics (AIMD). Dissociation and diffusion barriers have been calculated in order to understand surface oxidation and electronic properties at the atomic scale. We show that oxygen diffusion depends on the oxygen molecule orientation. Furthermore, we show that oxygen substitutional is stable at room temperature, which helps solving the puzzle of oxygen interaction with 2 H-MoS2.