Electrochemical Characterization of Carbon Felt Electrodes for Bulk Electrolysis and for Biocatalyst-Assisted Electrolysis

A sheet of carbon felt employed as an electrode exhibits characteristic voltammeteric waves for the electrolysis of solutions reflecting a three‐dimensional fiber structure of the electrode, in which the solutions both inside and outside the felt electrode undergo electrolysis. The electrolysis behavior can be characterized by three parameters: for the electrolysis of the outside solution, and l and for that of inside solution. expresses the effective outer surface area, and l and the average distance between the carbon fibers and the effective total surface area of the fibers constituting the felt electrode, respectively. It is shown that chronoamperometry provides a useful means of determining these parameter values. The value of , , (m is the mass of the felt electrode) is in the range of the reported values for the surface area per unit weight of carbon felts, and l is in fair agreement with the average distance between the fibers measured with an optical microscope. It is shown that and l are important parameters determining the rate of bulk electrolysis of a given volume of stirred solution, and that is a key parameter determining the magnitude of the current for biocatalyst‐assisted electrolysis. © 2000 The Electrochemical Society. All rights reserved.