Electrochemical Recovery of Cobalt from Cobalt Oxide in an Amide-Type Ionic Liquid with Low-Temperature Carbochlorination

Electrochemical recovery of metallic Co was attempted from CoO in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing 0.5 M BMPCl. CoO was dissolved in 0.5 M BMPCl/BMPTFSA with a carbochlorination reagent, C2Cl6, to form [CoCl4]2- at 150 °C. After the removal of electroactive C2Cl6 and byproducts, the electrochemical reduction of [CoCl4]2- was found to be possible on a glassy carbon electrode in the ionic liquid. Co nanowires were deposited by electrochemical reduction of [CoCl4]2- in 0.5 M BMPCl/BMPTFSA under an external magnetic field, which promoted the cathodic reduction and affected the morphology of the deposits. The deposited Co nanowires were found to be composed of crystalline Co nanoparticles by transmission electron microscopy.