Evaluating Contribution of Faradaic, Charging and Kinetic Currents in Potential Scan Hydrodynamic Voltammetry by Chemometrics Method

Abstract

Hydrodynamic electrochemical methods offer accurate and reliable approaches for obtaining kinetic information from the electrode surface and electrolyte in electrochemical redox systems. The presence of different mass and charge transfer mechanisms make these methods very complex. In the most suggested models, many assumptions are used and hence exact solutions are rarely obtained for the investigated systems. Moreover, the effect of some currents, such as charging current, is ignored in some equations. So, introducing a method for solving these systems without any constrain is of great concern. In hydrodynamic electrochemical methods, the total current is assumed to be composed of four main constituents including faradaic current, step charging current, induced charging current, and kinetic current. Multivariate curve resolution-alternating least squares (MCR-ALS) as a powerful chemometrics technique can be used for separation of total current to its four components. Since the understanding of kinetic current is helpful for computing the kinetic parameters, one purpose of this study is to extract kinetic current from the total measured current. The results showed that the MCR-ALS method could successfully deconvolute the total current into its four main constituents as described above. It was done simply and fast without applying any assumption or solving complicated numerical problems.