Fluctuations in electrochemical systems. II. Application to a diffusion limited redox process

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Abstract
A model of the stochastic behavior of the electrochemicalinterface is presented when a redox reaction limited by the diffusion of the reacting species occurs on the electrode surface. As shown in the first paper [J. Chem. Phys. 99, 7232 (1993)] it leads to the current–voltage curve, the electrochemical impedance and the power spectral density (PSD) of the electrochemicalnoise (current fluctuations in potentiostatic control or potential fluctuations in galvanostatic control). A comparison with experiment is performed for the potassium ferri‐ferrocyanide reaction on platinum. The noise generated by reaction‐diffusion is measured after eliminating the parasitic noise sources. At equilibrium the Nyquist theorem is experimentally checked, whereas far from equilibrium the measured excess noise is found to be in good agreement with the theory.