A temperature and electrochemical impedance spectroscopy analysis of nickel electrocrystallization from a Watts solution

Through the use of temperature as an investigational tool to elucidate the still-debated mechanism of Ni electrocrystallization from a Watts-type solu tion, it has been possible to determine the whole set of parameters governi ng the process. Starting from the simplest model capable of depicting the g eneral form of the stationary I-E curves, i.e., a two-monoelectronic-step m echanism involving an intermediately adsorbed species, we have shown that t he model may also be used for the analysis of electrochemical impedance spe ctroscopy (EIS) data. Both kinds of measurements, stationary and dynamic, l ead to one and the same set of parameters: transfer coefficients (alpha (i) = 0.72 +/- 0.02; alpha (2) = 0.44 +/- 0.02), intrinsic rate constants, and activation energies [E-a1 = (85 +/- 3) U mol(-1); E-a2 = (68 +/- 5) kJ mol (-1)]. The excellent accordance found in the temperature range explored (29 3-333 K) between experimental results and those calculated from the model d emonstrates the consistency of the whole procedure.