Determination of the Diffusion Coefficient from Impedance Data in the Low Frequency Range
Abstract
A new method is given for determining the diffusion coefficient or the Schmidt number of an electroactive species. The variation of the real part, relative to the imaginary part, of the electrochemical impedance, or of the electrohydrodynamic (EHD) impedance, at a rotating disk yields the diffusion coefficient without any assumption about the kinetics or any specific values for the electrode area or the solution concentration. This method may be used for all ordinary Schmidt number values (greater than 100).