Electrochemical Deposition of Metals Inside High Aspect Ratio Nanoelectrode Array: Analytical Current Expression and Multidimensional Kinetic Model for Cobalt Nanostructure Synthesis

Abstract

We report for the first time a comprehensive kinetic model based on the coupling of a cylindrical ultra-recessed electrode (Szabo, A.; Cope, D. K.; Tallman, D. E.; Kovach, P. M.; Wightman, R. M. J. Electroanal. Chem. 1987, 217, 417.) and the fractional area: this takes into account the derivation of a global diffusion coefficient in the steady-state current regime and considers the geometry of the nanoelectrode influence on the process. An experimental validation is done with the electrochemical deposition of cobalt inside a track-etched polymer membrane. This shows the kinetic dependence over the concentration, overvoltage, and geometrical parameters of the system. A decoupling of those parameters on the diffusion term is done, and a semianalytical model was derived for the case of cobalt. An estimation of the transference number and heterogeneous rate constant of the process is experimentally derived. This model provides the possibility of the prediction of electrosynthesis conditions with a quantitative evaluation of determining factors for the resulting nanostructure.