Electrochimica Acta, Vol.95, 237-245, 2013
Effect of uncompensated solution resistance on quasireversible charge transfer at rough and finite fractal electrode
Theory for the influence of uncompensated solution resistance on quasi-reversible charge transfer at an arbitrary rough electrode is developed. Detailed model analysis is performed for a finite fractal power spectrum; characterized with fractal dimension, lowest, highest cutoff-length scales of roughness and topothesy length (width) of the interface. The composite effect of the real and apparent kinetics is contained in L-H Omega which is summation of diffusion-kinetics (L-H) and diffusion-ohmic (L-Omega) coupling lengths. The current time response is therefore an interplay of L-H Omega, diffusion length, three finite fractal lengths and fractal dimension (manifesting themselves at different times). At short time, diffusion length is smaller than L-H Omega, current is proportionate to the ratio of real microscopic area and L-H Omega. These phenomenological coupling delays and curtails the onset of the anomalous response. As diffusion length becomes greater than L-H Omega, there is an emergence of intermediate anomalous region. However, limiting case of large L-H Omega approximately constant current is seen, without dynamic roughness effects. (c) 2013 Elsevier Ltd. All rights reserved.
Keywords:Uncompensated solution resistance;Quasireversible charge transfer;Rough and finite fractal electrode;Chronoamperometry;Diffusion