Copper nitride/silver nanostructures synthesized via wet chemical reduction method for the oxygen reduction reaction
Aleksandra Ścigała, Robert Szczęsny, Piotr Kamedulski, Marek Trzciński, Edward Szłyk
Abstract
Abstract This work presents attempts to synthesize silver-doped copper nitride nanostructures using chemical solution methods. Copper(II) nitrate and silver(I) nitrate were used as precursors and the oleylamine as a reducing and capping agent. Homogeneous Cu 3 N/Ag nanostructures with a diameter of ~ 20 nm were obtained in a one-pot synthesis by the addition of the copper(II) salt precursor to the already-synthesized silver nanoparticles (Ag NPs). Synthesis in a two-pot procedure performed by adding Ag NPs to the reaction medium of the Cu 3 N synthesis resulted in the formation of a Cu 3 N@Ag nanocomposite, in which Ag NPs are uniformly distributed in the Cu 3 N matrix. The morphology, structure, and chemical composition of the obtained specimens were studied by TEM, XRD, XPS, and FT-IR methods, while optical properties using UV–Vis spectroscopy and spectrofluorimetry. The band gap energy decreased for Cu 3 N/Ag ( E g = 2.1 eV), in relation to pure Cu 3 N ( E g = 2.4. eV), suggesting the insertion of Ag atoms into the Cu 3 N crystal lattice. Additionally, Cu 3 N and Cu 3 N/Ag nanostructures were loaded on graphene (GNP) and tested as a catalyst in the oxygen reduction reaction (ORR) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Cu 3 N/Ag-modified GNP hybrid material revealed catalytic activity superior to that of Cu 3 N-based GNP hybrid material and pure GNP, comparable to that of a commercial Pt/C electrode. Graphical Abstract