A Novel Way for Preparing Hexagonal-Shaped Mo₂N by NH₃ Reduction of Fe-Doped h-MoO₃

In the work, the temperature-programmed reduction reaction between NH₃ and h-MoO₃ under different conditions was investigated in order to prepare Mo₂N. Various technologies such as XRD, FESEM, and thermodynamic calculation were adopted to analyze the experimental data. The results demonstrated that the formation of Mo₂N primarily involved two stages: the reduction of h-MoO₃ to MoO₂ and the nitridation of MoO₂ to Mo₂N. In the reduction stage, both NH₃ and H₂ acted as the reducing agents; while only NH₃ acted as the nitridizing agent during the nitridation stage. The results also showed that when pure h-MoO₃ was used, the resulting Mo₂N exhibited an irregular granular morphology, differed significantly from the hexagonal structure of raw material. However, when Fe-doped h-MoO₃ was used, the resulting Mo₂N maintained the overall hexagonal shape with a loose and porous surface structure, which provided a new way for preparing hexagonal-shaped Mo₂N. The possible mechanism of morphological evolution was also illustrated.