USE OF SENSITIVITY ANALYSIS-METHODS IN THE MODELING OF ELECTROCHEMICAL TRANSIENTS - PART 2 - MODEL EXPANSION AND MODEL-REDUCTION

We propose a systematic and mathematically rigorous procedure of perfo rming the expansion or reduction of kinetic models arising in the area of electrochemical transient modelling. The procedure is based on the use of sensitivity analysis and involves calculation of first-order s ensitivity coefficients of the transient curves, with respect to the p arameters of various candidate or inherent model components (e.g. rate constants of elementary reactions in the reaction mechanisms). By con fronting the sensitivity coefficients with the deviations of simulated transients from experimental curves, decisions can be taken as to whe ther a particular model component should be added to or removed from t he model. The utility of this procedure is verified by its application to selected cyclic voltammetric data for two example electrochemical problems: anodic oxidation of 2, 2', 3, 3',4, 4', 5, 5'-octamethyl-1,1 '-bipyrrole in dichloromethane at a Pt stationary disk electrode (mode l expansion from E-rev to ErevCirr and cathodic reduction of bis([2(2) ] paracyclophane) Ru(II) bis(tetrafluoroborate) in propylene carbonate at a glassy carbon stationary disk electrode (model reduction from Er evErev-DISP to ErevErev). The procedure may become part of a wider, la rgely automated computer-aided strategy of developing kinetic models i n electrochemistry. (C) 1998 Elsevier Science S.A. All rights reserved .