Estimation of electrode kinetic and uncompensated resistance parameters and insights into their significance using Fourier transformed ac voltammetry and e-science software tools

Abstract In transient forms of voltammetry, quantitative analysis of electrode kinetics and parameters such as uncompensated resistance ( R u ) and double layer capacitance ( C dl ) are usually undertaken by comparing experimental and simulated data. Commonly, the skill of the experimentalist is heavily relied upon to decide when a good fit of simulated to experimental data has been achieved. As an alternative approach, it is now shown how data analysis can be based on implementation of e-science software tools. Previously, a standard heuristic data analysis approach applied to the oxidation of ferrocene in acetonitrile (0.1 M Bu 4 NPF 6 ) at a glassy carbon electrode using higher order harmonics available in Fourier transformed ac voltammetry implied that the heterogeneous charge transfer rate constant k 0 is ⩾0.25 cm s −1 with the charge transfer coefficient ( α ) lying in the range of 0.25–0.75. Application of e-science software tools to the same data set allows a more meaningful understanding of electrode kinetic data to be provided and also offers greater insights into the sensitivity of the IR u (Ohmic drop) on these parameters. For example, computation of contour maps based on a sweep of two sets of parameters such as k 0 and R u or α and k 0 imply that α is 0.50 ± 0.05 and that k 0 lays in the range 0.2–0.4 cm s −1 with R u around 130 Ohm. Quantitative evaluation of k 0 , α and R u for the quasi-reversible [ Fe ( CN ) 6 ] 3 - + e ⇌ [ Fe ( CN ) 6 ] 4 - process at a glassy carbon electrode in aqueous media is also facilitated by use of e-science software tools. In this case, when used in combination with large amplitude Fourier transformed ac voltammetry, it is found for each harmonic that k 0 for the electrode process lies close to 0.010 cm s −1 , α is 0.50 ± 0.05 and R u is ⩽10 Ohm.