Electrochemistry of Iodide in Propylene Carbonate: II . Theoretical Model

An algorithm based on Duhamel's superposition integral is used to simulate cyclic voltammograms for iodide electro-chemistry on platinum in propylene carbonate. The electrochemistry is represented by the reaction sequence 3I/sup -/ ..-->.. I/sub 3//sup -/ + 2e/sup -/ (I) 2I/sub 3//sup -/ ..-->.. numberI/sub 2/ + 2e/sup -/ (II) where reaction (I) is rate limited (Butler-Volmer kinetics) and reaction (II) is reversible (Nernst equilibrium behavior). Since the nonunity stoichiometries and Butler-Volmer kinetics in the reaction sequence prohibit the use of analytical solution techniques, the superposition-integral algorithm is used as a fast and accurate method for the numerical simulation. The simulated voltammograms for the iodide system agree very well with experimental observations and support the proposed reaction sequence.