Thermodynamic assessment of the Mo-S system and its application in thermal decomposition of MoS2

The Mo-S system is crucial to extractive metallurgy, tribology, and various possible applications in design and fabrication of novel two-dimensional (2D) materials. First-principles calculations were utilized to compute the enthalpies of formation of molybdenum sulfides at 0 K and the heat capacity of Mo2S3 up to 960 K. A critical evaluation of the thermodynamic properties, phase equilibria, and phase diagram information in the literature was carried out to facilitate the thermodynamic optimization of the Mo-S system. The obtained thermodynamic description of the Mo-S system can satisfactorily represent most of the reliable thermodynamic and phase diagram information. Pressure-temperature (P-T), pressure-composition (P-x), and temperature-composition (T-x) diagrams of the Mo-S system were utilized to study the thermal decomposition of MoS2 for raw Mo production. Reduced pressure and high temperature are thermodynamically favorable conditions for the MoS2 reduction process.