Original Synthesis of Molybdenum Nitrides Using Metal Cluster Compounds as Precursors: Applications in Heterogeneous Catalysis

摘要

Transition metal nitrides (TMN) form a class of materials with unique physical and chemical properties. Among them, molybdenum nitrides are mainly used as high-performance magnets or catalysts for a wide range of reactions. This work aims at developing innovative syntheses to prepare nanostructured TMN from metallic clusters for heterogeneous catalysis. The use of a nanoscale precursor such as (TBA)(2) Mo6Br14 (TBA = tetrabutylammonium = (C4H9)(4)N+) enables us to reach different molybdenum nitride compositions (Mo2N, Mo5N6) by thermal reaction under ammonia at relatively low temperatures. Such a novel synthetic approach highlights the prime importance of the starting material to stabilize specific stoichiometries. The impact of this new synthetic route is characterized by several techniques including electron probe microanalysis and high-resolution transmission microscopy. Moreover,catalytic properties of these potential cost-effective catalysts are investigated for the Water-Gas Shift Reaction.