Synthesis, Structure, and Electrochemical Characterization of Nanocrystalline Tantalum and Tungsten Nitrides

Nanocrystalline tantalum and tungsten nitrides were synthesized by a two‐step ammonolysis reaction of transition metal chlorides. The first step involves ammonolysis of tantalum and tungsten chlorides at room temperature using anhydrous chloroform as the solvent. A second step consists of heat treatment of these as‐prepared powders under anhydrous NH 3 atmosphere leading to the formation of tantalum and tungsten nitride nanocrystallites at relatively low temperature (600°–675°C). The ammonolysis, nitridation, structure, morphology, surface area, density, and electronic conductivity of the nitrides obtained were studied and characterized. The electrochemical responses of these nitrides were also measured by cyclic voltammetry using 1 M KOH electrolyte.