Highly accurate and inexpensive procedures for computing chronoamperometric currents for the catalytic EC' reaction mechanism at an inlaid disk electrode

In the former studies [L. K. Bieniasz, Electrochim. Acta 199 (2016) 1-11, 259 (2018) 1068-1080] a rigorous theory of chronoamperometry was elaborated, together with efficient and highly accurate computational procedures, for a single charge transfer reaction at an inlaid disk electrode, assuming diffusion transport and limiting current conditions. By extending this theory, in the present work theoretical formulae are derived, for transient and steady state Faradaic currents corresponding to the catalytic EC' reaction mechanism, assuming equal diffusion coefficients of the redox couple. Using the new formulae, inexpensive and highly accurate procedures of computing the currents are developed. The procedures are implemented in C++ and they are characterised by relative errors comparable to or smaller than those previously obtained in the absence of the catalytic homogeneous reaction (at the level of about +/- 10(-15) in the worst cases). Calculation of transient currents involves numerical integration by means of a double exponential quadrature. Average computational time varies between about a microsecond and a millisecond (per single current value), on a contemporary laptop computer. The procedures can be useful for testing/validating diverse modelling and simulation techniques, and for experimental data analysis. (C) 2018 Elsevier Ltd. All rights reserved.