Abstract: The nitrided Mo/Al₂O₃ catalysts were prepared by temperature programmed reaction between NH₃ and MoO₃/Al₂O₃. XRD and EXAFS methods were used for the structural characterization. The results of XRDshow that the molybdenum species in the supported samples exist as a dispersed MoO₃ phase before nitriding. After nitriding, most of the molybdenum species were nitrided to form γ-Mo₂N. The lower intensity of the radial structure functions of Mo Kedge and the smaller coordination number of Mo-Nshells accordingly indicate that the γ-Mo₂Nin the supported samples possesses a high dispersion, the lower the loading of Mo, the higher the dispersion of γ-Mo₂Non alumina. From the view of coordination distance, it is found that with the increase of dispersion of γ-Mo₂N, the Mo-N distance is a little shortened, which may be resulted from the nano shortening phenomenum. The values of disorder factors show that the γ-Mo₂N phase in the supported samples has big thermal and structural disorder extent, and with the increase of its dispersion, both the thermal and structural disorder factors increase.

Key words: Mo₂N/Al₂O₃ Catalysts, Preparation, Structural Characterization, EXAFS