In this work, the liquid phase plasma reduction method was applied to prepare the spherical nickel nanoparticles from the solution of nickel chloride. A bipolar pulsed power supply was used to generate discharges in the aqueous solutions. Nickel nanoparticle peaks produced by surface plasmon absorption were observed around 381 nm with electrical discharge. Spherical nickel nanoparticles were mostly observed in this study, pentagonal nanoparticles were also observed occasionally. The TEM image showed that the average particle size varied from 10 to 200 nm in diameter as discharge time was increased. Many spots could be seen in the ED pattern for polycrystalline particles.

The liquid-phase plasma reduction method has been applied to prepare iron nanoparticles from iron chloride solution using a bipolar pulsed electrical discharge system. The excited states of atomic iron, hydrogen, and oxygen as well as the molecular bands of hydroxyl radicals were detected in the emission spectra. The iron nanoclusters formed at the initial stage convert to dispersion of small iron nanoparticles, which then grows slowly to form anisotropic, tetragonal shape. The cationic surfactant of CTAB was shown to exhibit a large influence on the particle generation procedure.