Interaction of O2 with monolayer MoS2: Effect of doping and hydrogenation

Abstract

The interaction of O2 with doped monolayer MoS2 and the effect of hydrogenation are studied by first-principles calculations coupled with the CI-NEB method. Surface chemically inertness of the MoS2 (001) plane can be broken by doping with Co, Ni and Cu atoms. Impurity levels are induced around the Fermi level and lead to the decrease of band gap, which is beneficial to the adsorption of O2 molecule. The activated oxygen atoms are produced through a dissociation reaction. The introduction of hydrogen atoms into the surface of doped MoS2 system presents favorable effect for O2 adsorption and dissociation. More impurity levels appear in the hydrogenated MoS2-Co/Ni system, and more electrons are localized at 3d orbital of Co/Ni atom, these systems all present excellent adsorption capacity. Hydrogenation reaction occurs by a hydrogen adatom smoothly migrating to the adsorbed O2 with the formation of OOH radical. The elongated OO bond of OOH radical can be dissociated with a lower activation energy barrier, producing an OH radical and activated oxygen atom. Our theoretical studies suggest that the doped monolayer MoS2 system is effective for capturing O2 molecule, and the hydrogenation is found to facilitate adsorption and dissociation of O2 molecule.