Electrodeposition of Nickel From an Amide-Type Ionic Liquid Under a Magnetic Field

Abstract

Aprotic ionic liquids are considered to be used as the promising electrolytes for electrodeposition of wide variety of metals and alloys. Nickel is one of the ferromagnetic metals and can be deposited in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Ni(TFSA)2.[1] Furthermore, Ni nanoparticles were prepared in the ionic liquid by potentiostatic cathodic reduction at a negative potential region.[2] Recently, we reported that the nanowires of a ferromagnetic metal and alloy could be deposited electrochemically by applying a static magnetic field without any template.[3-5] The formation of metal nanowires is considered to be due to the magnetization and self-organization of the nanoparticles at the electrode-electrolyte interface. Thus, the similar nanowires are expected to be obtained for ferromagnetic metals like Ni. In the present study, electrodeposition of Ni was conducted in BMPTFSA containing Ni(TFSA)2 under a static magnetic field.The cathodic reduction of Ni(II) was observed in the cyclic voltammogram of a glassy carbon (GC) electrode in BMPTFSA containing Ni(TFSA)2, as reported previously.[1] An increase in the cathodic peak current and the positive shift of the onset potential of the cathodic current were observed when a magnet was attached on the backside of the GC electrode. Granular deposits were observed after potentiostatic cathodic reduction without the magnet. However, nanowires were deposited on the GC electrode with the magnet, verifying the electrodeposition of ferromagnetic metals in the ionic liquid under a magnetic field leads to the formation of the nanowires.