Theoretical Study of the MoS₂ (100) Surface:  A Chemical Potential Analysis of Sulfur and Hydrogen Coverage. 2. Effect of the Total Pressure on Surface Stability

Abstract

We investigate theoretically, by quantum DFT calculations, the adsorption of H 2 molecules on the [100] MoS 2 surfaces, considering various edge sulfur stoichiometries. Depending on the nature of the gas phase, the adsorption energies vary from strongly positive values to strongly negative ones. Using these energies, we have constructed a thermodynamic diagram, which gives the stoichiometry of the edges and the nature of the adsorbed hydrogen atoms as a function of the total pressure and of the P H 2 S / P H 2 partial pressure ratio and determines the best conditions to examine the S−H groups using spectroscopic techniques.