Kinetic studies using a rotating cylinder electrode. Part I. Electron transfer rates in ferrous/ferric sulfate on platinum

Abstract

A Pt rotating cylinder electrode has been used to study the mass transfer and kinetic characteristics of the Fe3+/Fe2+ redox reaction in a sulfate electrolyte. Mass transfer data indicate that limiting currents depend on the cylinder rotation speed to the 0.70 power. A model has been developed to extract kinetic parameters from mixed diffusion-kinetic data; according to this model, diffusion corrected kinetic currents at each potential are obtained by plotting inverse measured currents vs. cylinder rotation speed to the -0.70 power and extrapolating the resulting straight lines to infinite rotation speed. Kinetic parameters for the Fe3+/Fe2+ reaction obtained on the cylinder electrode using this model coincided with values obtained for the same reaction on a rotating disk electrode using the Jahn-Vielstich model. It was thus concluded that rotating cylinders yield kinetic results which are equally satisfactory with those obtained from rotating disks. © 1986.