Ni₂Mo₃N: crystal structure, thermal properties, and catalytic activity for ammonia decomposition

Ni 2 Mo 3 N was synthesized by ammonolysis of NiMoO 4 , prepared by a sol-gel-based modified Pechini route. X-ray powder diffraction measurements confirmed that Ni 2 Mo 3 N crystallizes in a filled β -Mn type (cubic space group P 4 1 32) with a lattice parameter of a = 6.6338 Å. Group theoretical methods were applied to elucidate the relation between the crystal structure of Ni 2 Mo 3 N and that of the rock salt type. The high-temperature behavior was investigated in-situ by X-ray diffraction measurements in flowing ammonia gas at temperatures up to 875 °C. Ni 2 Mo 3 N exhibits significant catalytical activity for ammonia decomposition, which is critically discussed in comparison to literature.