In the present paper, using a cathodic pin-to-solution electrical discharge electrolysis setup, interaction of the atmospheric air plasma with aqueous solution of copper nitrate and its possibility for synthesis of nano-materials is investigated. An AC (50 Hz) high-voltage power supply (5 kV) with rectified current is used for electrical discharge of the air between a metal pin and the solution surface. The experiment shows that, immediately after beginning of the discharge, a pale green-blue powder is generated at the plasma-solution interface. Characterization of the powder by XRD and EDS analyses shows that it is Cu2(OH)3NO3. FESEM images reveal that the synthesized powder consists of crystalline micro-plates with nanometer (~200 nm) thicknesses and micrometer (~2 μm) widths. It seems that generation of OH ions and radicals in the air plasma as well as dissociation of water molecules by energetic plasma ions is responsible for the powder synthesis.
