CLOSED-FORM APPROXIMATE EXPRESSIONS FOR THE ELECTROCHEMICAL RESPONSE OF MICROELECTRODES IN THE ZERO-RANGE LIMIT

We show that the electrochemical response of one or more microelectrodes can be described, in the limit of small size, by closed-form solutions of diffusion-kinetic equations, which, under appropriate and well-defined conditions, should give a good approximation to the actual response. The predictions of the analytical solutions for the diffusion-kinetic model are compared with microelectrode array experiments of Bard et al. and show excellent agreement. The analytical results make clear the various scaling properties of the solution, as a function of electrode size and spacings, as well as indicating the range of validity of the diffusion-kinetic model itself.