the inset of Fig. 2b. Upon analysis of the voltammogramcurve for a
pH 2.70 solution (Fig. 2a), during the scan through negative poten-
tials, no processes were observed until a potential of −0.34V was
reached. From this potential, an increase in current density was
observed, reaching a maximum value of −0.46V. As shown in the
inset of Fig. 2b, however, no mass variation was observed until a
potential of −0.75V was achieved. From this potential, the current
density increased quickly prior to reaching the inversion potential
(−1.00V), which was followed by a mass increase on the platinum
electrode. The voltammogramcurve obtained for cobalt electrode-
position in a pH 5.40 solution presents similar behavior; however,
during the cathodic scan, the current density begins to increase
at −0.70V. At this potential, cobalt deposition onto the platinum
electrode was initiated, as shown in the mass variation profile of
platinum (inset of Fig. 2b). Current density increased continually
until −1.00V, due to the proton discharge reaction that occurs
simultaneously with metallic cobalt deposition.