One-step template-free electrosynthesis of cobalt nanowires from aqueous [Co(NH3)6]Cl3 solution

The discovery and the use of the self-organization of nanostructures are keys to realizing their large-scale syntheses and industrial applications. We now describe a one-step template-free electrochemical method to prepare Co nanowires. A simple electroreduction of an aqueous [Co(NH3)6]3+ solution gave a deposit composed of abundant Co nanowires with lengths up to 60 μm and an average diameter of 240 nm. The electrogenerated Co was self-organized to form the nanowires under specific electrolytic and solution conditions. Various electrochemical investigations revealed the following electrodeposition reaction of [Co(NH3)6]3+ + 3e → Co + 6NH3 and the growth of the wire from its apex. These results may contribute to future nanotechnologies of magnetic storage and field emission devices based on the mass-production of Co nanostructures.