Self-Combustion Synthesis of Novel Metastable Ternary Molybdenum Nitrides
Ternary metal nitrides are a promising class of functional materials, but their variety has been limited by the challenging nature of nitride synthesis. Here, we demonstrate a facile self-combustion synthesis route to novel ternary molybdenum nitrides. The room temperature mixing of NaNH 2 , MoCl 4 , and 3d transition metal chlorides, such as MnCl 2 , FeCl 2 , and CoCl 2 , initiates a highly exothermic metathesis reaction, which is thermodynamically driven by the formation of stable NaCl, N 2 , and NH 3 byproducts. The rapid combustion reaction yields ternary rocksalt γ-TM x Mo 1-x N 0.5 nanoparticles (TM = Mn, Fe, Co) in just a few seconds. We calculate from DFT that these disordered ternary molybdenum nitrides are thermodynamically stable under the high-temperatures at which they form but are remnantly metastable when quenched to ambient conditions. Introduction of Mn, Fe, and Co into γ-Mo 2 N is found to change its magnetic properties and to enhance its oxygen reduction catalytic activities. Furthermore, our work demonstrates self-combustion synthesis as a simple but powerful route for the realization of novel ternary intermetallic nitrides with emergent functionality.