Energetics of Oxidation in MoS2 Nanoparticles by Density Functional Theory

Density functional theory is used to determine the energetics of atomic oxygen substitution in an infinite single MoS2 trilayer and on the edges of six structurally distinct MoS2 nanoparticles. The wide range in the oxidation energy (-0.9 to -2.4 eV) is found to be primarily due to differing degrees of charge transfer between atoms of interest and the resulting variation of the electrostatic energy of the system. For the edges at which no S-S bond is formed, a lower Mo-coordinated site is generally more susceptible to oxygen substitution than a higher Mo coordinated site. For the edges at which a S-S bond is formed, the analyses of projected local electronic density of states suggest that the oxidation energy is a result of both differences in the electrostatic energy and local competition of binding energy of the covalent bonds.