Interpretation of AC surface current density by deconvolution of potentialdifferences in solution

In localized electrochemical impedance techniques, the measurable AC potent ial difference in solution is related to the AC surface current distributio n simply by using Ohm's law. However, this relationship is not true for the cases in which current distribution is non-uniform. In order to correctly obtain the surface current density, deconvolutions of the solution potentia l difference using the base line stripping procedure and the Fast Fourier T ransform method have been simulated and discussed. A more accurate spatial estimate of the surface current density distribution can be obtained by dec onvoluting the measured potential difference distribution in the solution t han by simply using Ohm's law. The accuracy of the deconvolution using the base line stripping procedure is greatly dependent on the errors of measure ment, and experimental data with a very low noise level are therefore requi red. Deconvolution by a Fast Fourier Transform is also very sensitive to no ise and discontinuity in the potential difference distribution, but the sen sitivity can be dramatically reduced to an acceptable level by using a low pass filter. (C) 2000 Elsevier Science Ltd. All rights reserved.