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.