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 solution, it has been possible to determine the whole set of parameters governing the process. Starting from the simplest model capable of depicting the general form of the stationary I-E curves, i.e., a two-monoelectronic-step mechanism involving an intermediately adsorbed species, we have shown that the model may also be used for the analysis of electrochemical impedance spectroscopy (EIS) data. Both kinds of measurements, stationary and dynamic, lead 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 (293-333 K) between experimental results and those calculated from the model demonstrates the consistency of the whole procedure.