Voltammetric study and electrodeposition of copper in 1-butyl-3-methylimidazolium salicylate ionic liquid

The voltammetric behavior of cuprous ions has been studied at disk electrodes of glassy carbon and polycrystalline platinum in a new hydrophilic 1-butyl-3-methylimidazolium salicylate ionic liquid (BMI-SAL IL). Cuprous ions Cu(I) were introduced into the IL by the anodic dissolution of a Cu wire electrode or by the addition of CuCl. This air- and water-stable hydrophilic IL is very similar to dicyanamide (DCA)-based ILs because both DCA anions and salicylate (SAL) anions have very strong ligand properties; therefore, many metal salts, such as metal halides, are very soluble in this IL. However, the source of SAL anions, sodium salicylate, is considerably cheaper than sodium dicyanamide salt. The potentiostatic electrodeposition of copper onto iron substrates has also been investigated in this study. The surface morphologies of the copper deposits were significantly altered by the electrodeposition potential; granular, mirror-like, and porous copper deposits could be obtained at different negative potentials. The activity of the copper deposit-modified iron electrodes toward the electrochemical nitrate reduction in alkaline solutions was found to significantly depend on the surface morphologies. The granular and the porous surfaces showed better activities. The mirror-like surface, however, had no activity on the electrochemical nitrate reduction.

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► A new, cheap, and air- and water-stable ionic liquid BMI-SAL was prepared.
► Metal halides are soluble in this ionic liquid.
► Voltammetric study and electrodeposition of Cu was carried out.
► Electrodeposition potentials significantly affect the surface morphologies of Cu.
► The surface morphology determines the electrode activity toward nitrate reduction.