6533b862fe1ef96bd12c6165

RESEARCH PRODUCT

Determination of the electroactive area of graphite+polyethylene composite electrodes. Uncompensated resistance effects and convolution analysis of chronoamperograms

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In this work, it is shown how the convolution analysis of chronoamperograms permits the observation of the uncompensated resistance and the natural convection effects on the electrochemical response of potassium ferrocyanide. The uncompensated resistance causes the current intensity to follow the Cottrell equation only after a certain critical time. The convolution of chronoamperograms worked out at different integration times shows a maximum when this time is long enough. The classical diffusion equations cannot explain this phenomenon themselves. The development of this maximum associated with the natural convection is discussed. If both these factors, the ohmic drop and the natural convection, together with the roughness factor, are considered, the electroactive surface for the composite can be obtained. Theoretical expressions have been derived for reversible and quasi-reversible systems to support the discussion of the experimental results.