Solution/Ammonolysis Syntheses of Unsupported and Silica-Supported Copper(I) Nitride Nanostructures from Oxidic Precursors.

Herein we describe an alternative strategy to achieve the preparation of nanoscale CuN. Copper(II) oxide/hydroxide nanopowder precursors were successfully fabricated by solution methods. Ammonolysis of the oxidic precursors can be achieved essentially pseudomorphically to produce either unsupported or supported nanoparticles of the nitride. Hence, CuN particles with diverse morphologies were synthesized from oxygen-containing precursors in two-step processes combining solvothermal and solid-gas ammonolysis stages. The single-phase hydroxochloride precursor, Cu(OH)Cl was prepared by solution-state synthesis from CuCl·2HO and urea, crystallising with the atacamite structure. Alternative precursors, CuO and Cu(OH), were obtained after subsequent treatment of Cu(OH)Cl with NaOH solution. CuN, in the form of micro- and nanorods, was the sole product formed from ammonolysis using either CuO or Cu(OH). Conversely, the ammonolysis of dicopper trihydroxide chloride resulted in two-phase mixtures of CuN and the monoamine, Cu(NH)Cl under similar experimental conditions. Importantly, this pathway is applicable to afford composite materials by incorporating substrates or matrices that are resistant to ammoniation at relatively low temperatures (ca. 300 °C). We present preliminary evidence that CuN/SiO nanocomposites (up to ca. 5 wt.% CuN supported on SiO) could be prepared from CuCl·2HO and urea starting materials following similar reaction steps. Evidence suggests that in this case CuN nanoparticles are confined within the porous SiO matrix.