Heterogeneous redox catalysis at conducting polymer ultramicroelectrodes

Abstract

The theoretical analysis of the steady state current response expected for a polymer modified ultramicroelectrode when the latter is operating under batch amperometric conditions is discussed. In particular, the interplay between the substrate reaction and diffusion within an electronically conducting polymer is examined. Six distinct limiting kinetic situations are developed and presented schematically in the form of a kinetic case diagram. It is predicted that the reaction order for the steady state catalytic current response with respect to bulk substrate concentration, mediator concentration and electrode radius produces a distinct triplet of characteristic values for each kinetically limiting situation.