Guidelines for the synthesis of molybdenum nitride: Understanding the mechanism and the control of crystallographic phase and nitrogen content

Bulk (Mo2N) and supported molybdenum nitride (Mo2N/TiO2, Mo2N/CeO2) were synthesized by reduction-nitridation of bulk MoO3 under a mixture N2/H2. We investigated the mechanism formation nitrides coupling elemental analysis, in situ ex XRD, Raman spectroscopy, XPS/UPS spectroscopy DFT calculation. showed that it is possible to control crystallographic phase degree nitridation (i.e. nitrogen vacancies) adjusting parameters synthesis, including heating rate final temperature, nature, composition flow gas during reduction/nitridation cooling. demonstrated β-Mo2N γ-Mo2N go through same intermediates: bronze, MoO2 Mo. The depends mainly on temperature hourly space velocity employed as they impact crystallite size intermediates kinetics reduction nitridation. Molybdenum clusters (<0.5 nm) are formed TiO2.