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

Abstract

Herein we describe an alternative strategy to achieve the preparation of nanoscale Cu3N. 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, Cu3N 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, Cu2(OH)3Cl was prepared by solution-state synthesis from CuCl2·2H2O and urea, crystallising with the atacamite structure. Alternative precursors, CuO and Cu(OH)2, were obtained after subsequent treatment of Cu2(OH)3Cl with NaOH solution. Cu3N, in the form of micro- and nanorods, was the sole product formed from ammonolysis using either CuO or Cu(OH)2. Conversely, the ammonolysis of dicopper trihydroxide chloride resulted in two-phase mixtures of Cu3N and the monoamine, Cu(NH3)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 Cu3N/SiO2 nanocomposites (up to ca. 5 wt.% Cu3N supported on SiO2) could be prepared from CuCl2·2H2O and urea starting materials following similar reaction steps. Evidence suggests that in this case Cu3N nanoparticles are confined within the porous SiO2 matrix.

Surveying the Synthesis, Optical Properties and Photocatalytic Activity of Cu3N Nanomaterials

“…Nanomaterials 2022, 12, x FOR PEER REVIEW 6 of 25 particles [74]. Deshmukh et al synthesized Cu3N@SiO2 composites using a multistep approach [71].…”

“…Multistep synthesis approaches have also been applied to the synthesis of Cu 3 N. These approaches are used to reduce copper oxide nanoparticles produced in the first step of the synthesis, followed by nitration. For example, Szczesny et al synthesized Cu 3 N nanoparticles with diverse morphologies from oxygen-containing precursors using a twostep process that combines solvothermal and solid-gas ammonolysis stages [74]. In the first step, copper (II) chloride dihydrate was used as a precursor for the fabrication of copper (II) oxide and copper (II) hydroxide nanoarchitectures by solvothermal methods.…”

“…In the first step, copper (II) chloride dihydrate was used as a precursor for the fabrication of copper (II) oxide and copper (II) hydroxide nanoarchitectures by solvothermal methods. In the second step, Cu 3 N was obtained through ammonolysis of Cu(OH) 2 and CuO nanoparticles [74]. Deshmukh et al synthesized Cu 3 N@SiO 2 composites using a multistep approach [71].…”

“…The material displays high optical absorption and has therefore been applied to photovoltaics [119]. In the electronics industry, Cu 3 N has successfully shown optical data storage capabilities when coupled with an Al 2 O 3 protective layer [74]. The capacity to transform Cu 3 N under laser pulses of different wavelengths to Cu is the basis of optical data storage, measured in terms of changes in the reflectivity of the nanomaterial [80].…”

Copper Nitride: A Versatile Semiconductor with Great Potential for Next-Generation Photovoltaics

“…These methods involve the use of precursors such as Cu(hfac) 2 and [Cu(sBu-Me-amd)] 2 [21] to determine its resulting phase composition and morphology and to establish the growth rate [22,23]. Ammonolysis reactions can also be used to prepare bulk Cu 3 N powder samples [24], as well as thin films [25]. In addition, recent works have shown that Cu 3 N nanowire arrays can be synthesised by an ammonolysis reaction from copper (II) oxide precursors grown on copper surfaces deposited by electro or PVD in an ammonia solution [26,27].…”