화학공학소재연구정보센터
Journal of Electroanalytical Chemistry, Vol.594, No.1, 50-58, 2006
Extraction of a quantitative reaction mechanism from linear sweep voltammograms obtained on a rotating disk electrode. Part I: Theory and validation
In this work a method is set-up to extract the mass and charge transfer parameters quantitatively from linear sweep voltammetry with a rotating disc electrode (LSV/RDE) experiments. It requires the proposition of an appropriate mechanism for the reaction under study and its mathematical translation into an expression that analytically describes the voltammogram. Powerful parameter estimation algorithms (maximum likelihood combined with Gauss-Newton and Levenberg-Marquardt minimization methods) are used to adjust the values of these model parameters, in order to obtain a good agreement between experimental and modeled data. The values of the model parameters that give rise to the best match, characterize the system quantitatively. Moreover, the method provides error estimates of the obtained parameter values. However it is only after a statistical evaluation of the obtained results, that it is decided whether the model is able to describe the experiments or not. Compared to others, this method offers the advantage that it uses one integrated expression that accounts for mass and charge transfer steps, and this without simplifying their mathematical expressions. Other elementary reaction steps (like chemical reactions, migration, adsorption) can also be included, as long as their influence on the polarization curve is mathematically formulated. Another plus-point is that the whole polarization curve is considered, rather then just some part in which only mass or charge transfer are supposed to be rate determining. This approach has never before been used in electrochemical studies and the coupling of statistically founded parameter estimation techniques with LSV/RDE experiments is an important innovative point of this work. In the first article of this series the theoretical background is described. Furthermore, an evaluation of the proposed method on simulated experiments is given at the end of this manuscript. (c) 2006 Elsevier B.V. All rights reserved.