The Reduction of Various Nitrides under Hydrogen: Ni3N, Cu3N, Zn3N2 and Ta3N5

Metal nitrides may be of interest as potential sources of activated nitrogen which can be reacted with target organic molecules. Accordingly, the reduction of nitrogen within Ni3N, Cu3N, Zn3N2 and Ta3N5 under a 1/3 Ar/H-2 flow at elevated temperature has been determined as a simple test of lattice nitrogen reactivity. As anticipated by consideration of their stability, Ni3N and Cu3N are reduced completely at 250 A degrees C with up to 30 % of their total lattice nitrogen yielding ammonia. The elimination of N-2 results in the formation of pores which are particularly pronounced in the case of the denitrided Cu system. In the case of Zn3N2, the lattice nitrogen is less reactive with incomplete denitridation being observed at 400 A degrees C and the amount of ammonia produced being 15 % of the total nitrogen available. Although Ta3N5 contains the least reactive nitrogen of the four samples studied, it can be regenerated by ammonolysis which is an important consideration in any envisaged application.