Applied Surface Science, Vol.256, No.16, 4888-4893, 2010
Electrochemical behavior of cobalt from 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid
The electrodeposition of metallic cobalt from a 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid was investigated. The electrochemical behavior of Co(II) in the ionic liquid on a platinum working electrode at 60 degrees C was studied by cyclic voltammetry and chronoamperometry. The results from the cyclic voltammetry showed that the electrodeposition of metallic Co in the ionic liquid was an irreversible process and controlled by the diffusion of Co(II) on a platinum working electrode. The average value of alpha n(alpha) was calculated to be 0.35 and the diffusion coefficient (D-0) of Co(II) was calculated to be 1.76 x 10(-8) cm(2)/s at 60 degrees C. Chronoamperometric results indicated that the electrodeposition of Co on a platinum working electrode followed the mechanism of instantaneous nucleation and three-dimensional growth with diffusion-controlled. The cobalt plating was uniform, dense, shining in appearance with good adhesion to the platinum substrate at 60 degrees C. The scanning electron microscope (SEM) micrographs were used to confirm that the cobalt plating was denser and finer at 60 degrees C. Energy dispersive X-ray analysis (EDAX) pro. le showed that the obtained plating was pure cobalt. X-ray diffraction (XRD) pattern indicated that there was a preferred orientation direction and the average size of cobalt grains was 40 nm. (C) 2010 Elsevier B. V. All rights reserved.