Analysis of the Steady State and Transient Currents for a Rotating Disk Electrode under Surface Diffusion Limitation

A theoretical analysis is carried out of the current response under surface diffusion limitation for a rotating disk electrode. Two model surfaces have been considered, an array of active centers and a partially blocked surface. Equations are derived for the current response from both surface types, at the steady state and time dependent, under limiting surface diffusion over the inactive areas. A geometrical approximation of the array electrode to the partially blocked electrode is derived, to be used for cases with overlapping of surface diffusion areas. The practical application of the model results is discussed. The analysis allows determining surface diffusion parameters on electrodes with localized reactivity. (C) 2014 The Electrochemical Society. All rights reserved.