PREPARATION AND CHARACTERIZATION OF A NOVEL CLASS OF CATALYSTS - ULTRADISPERSED MOLYBDENUM OXYNITRIDES SUPPORTED ON NAEMT AND HEMT ZEOLITE

Decomposition under partial pressure of ammonia of Mo(CO)(6)EMT and su bsequent nitridation under flowing ammonia were used to prepare EMT ze olite-encaged molybdenum nitride clusters. The HRTEM and EDS measureme nts indicate that the final molybdenum phases were homogeneously dispe rsed, the final clusters' diameter being less than 10 Angstrom. X-ray diffraction (XRD) patterns and specific surface area measurements show ed that the EMT zeolite crystallinity was not affected by ammonia trea tments. Ammonia decomposition during the preparation step and X-ray ph otoelectron spectroscopy (XPS) data allowed us to assess the nitridic nature of the clusters for a nitridation temperature as low as 723 K.