Copper nanopowder synthesis by electrolysis method in nitrate and sulfate solutions

•Electrolysis medium, type of current and nitric acid concentration were studied.•Powders in the sulfate medium in pulse state with the PVP were less than 200 nm.•Powders in nitrate medium in direct state without additive were less than 100 nm.•Direct current results in the nitrate medium were better than the pulse current.•Efficiency of nitrate medium current was significantly less than the sulfate medium.

Chemical electrodeposition (electrolysis) is one of the methods which can be used for production of high-purity copper powder. In this work, synthesis of nano-sized copper powder particles by means of electrolysis has been investigated. Parameters such as electrolysis solution, type of current (direct and pulse), and nitric acid concentration have been studied. The media of study were nitrate and sulfate. Particle size of powder obtained by the direct current in the nitrate solution was even smaller than those of the pulse current state in the sulfate. Thus, the nitrate solution was chosen for investigation of the nitric acid concentration (25–45 g/L). The obtained powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and laser particle size analyzing (LPSA) methods. The powders produced in the sulfate solution (in pulse state along with the polyvinylpyrrolidone (PVP) additive) were less than 200 nm in size; however, those produced in the nitrate solution (in direct state without additive) were less than 100 nm. Current efficiency of the nitrate solution (about 30%) was significantly less than that of the sulfate solution (about 70%). The powders produced in the nitrate solution were of high purity, similar to the sulfate solution.

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