Phase equilibrium diagram and phase transformation for preparation of Mo2C: Thermodynamic study and experimental verification

Because of the extended application in catalytic reactions, numerous kinds of methods are developed for synthesis of Mo2C catalysts. The repeated efforts on exploring the reaction conditions caused a huge waste of materials and a large consumption of the energy from researchers. In this work, a widely applicable guidance of phase equilibrium diagrams for Mo2C production was provided by thermodynamic calculation. The phase equilibrium diagrams of both MoO3–C and MoO3–Na2CO3–C (Na2MoO4–C) systems were plotted, which reveals the reaction mechanisms and suggests the reaction conditions for preparation of Mo2C. According to the phase equilibrium diagrams of Na2MoO4–C system, the reaction routes of molybdenum determined by the reduction temperature will experience Na2MoO4, Mo2C, Mo in carbothermic reduction procedure, which is instructive for synthesis of Mo2C catalysts. Results of this work will provide a theoretic guidance for the generation of Mo2C, which will make the synthesis of molybdenum carbides much easier.