(226a) Production of Molybdenum Nitride and Carbide Dispersed Nanostructured Crystallites using Ultrasounic Irradiation

Molybdenum nitride (Mo₂N) has been previously examined by this group for hydrodesulfurization (HDS) catalysis due to its relatively high resistance to sulfur poisoning and ample surface area. Mo₂N nanoparticles synthesized by this group using an ultrasonic dispersion method have been observed in the 4 to 15 nm range from TEM and STM measurements. The excellent mechanical and thermal resistance properties of transition metal nitrides and carbides make them desirable as potential nanofiller materials for high strength, flame-resistant nanocomposites.

Powders of molybdenum nitride (Mo₂N) and molybdenum carbide (Mo₂C) were prepared by me= ans of the temperature programmed reaction (TPR) method. Mo₂N was produced by the TPR of molybdenum (VI) oxide (MoO₃) and a reactant gas mixture of nitrogen/hydrogen. Mo₂C was synthesized in s= imilar fashion by reacting MoO₃ with a pre-selected molar ratio of methane/hydrogen gas mixture. Dispersed nanostructured crys= tallites of Mo₂N and Mo₂C powders were synthesized via ultrasonic irradiation. Ultrasonic dispersion was employed by creating sl= urries of the metal nitrides and carbides with de-ionized water and subjecting the samples to ultrasound energy by means of an ultrasonic horn. Samples were characterized using room temperature X-ray Diffraction (RTXRD), elem= ental analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).