Simple new synthesis of copper nanoparticles in water/acetonitrile mixed solvent and their characterization

Copper nanoparticles were successfully synthesized by the borohydride reduction of copper nitrate salt in water/CH₃CN mixed solvent under inert argon-purged conditions. Cu nanoparticles were synthesized in large-scale production for the first time by introducing CH₃CN into water and preventing oxidation during the preparation of nanoparticles. Nanoparticles were characterized by using UV-visible absorption spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. High resolution TEM pictures showed the formation of homogeneous cubic-structured copper nanoparticles with sizes less than 100 nm. This new kind of synthesis method shows the excellent stability compared with that of citrate-protected copper nanoparticles, which may provide an efficient way to improve the fine tuning of the structure and size of copper nanoparticles.