Kinetic study of bromide adsorption on Hg by a combined equivalent-circuit reaction-mechanism modeling of EIS data

A quantitative kinetic description of the adsorption of bromide on mercury is developed by combination of complementary approaches to the adsorption impedance data. Equivalent-circuit modeling is matched with mechanistic models. The resulting descriptions permit the estimation of absolute adsorption and desorption rate constants for Br- on Hg electrode by assuming either a Langmuir or a Frumkin adsorption isotherm. It is found that adsorption-desorption dynamics for the Hg/Br- system is well described by the transfer function based on the Frumkin isotherm, indicating a predominant role of adsorbate-adsorbate interactions. (C) 2011 Elsevier B.V. All rights reserved.