Galvanostatic pulse followed by coulostatic impulse with reversed sign: A new double-pulse method for the determination of the kinetic parameters of electrode reactions I. Theory and classification

Abstract

A new double pulse method is presented in which a galvanostatic pre-pulse is followed by a coulostatic impulse with reversed sign. The coulostatic charge density selected is such that the overvoltage-time curve starts with a horizontal tangent after the impulse has ceased. As both the net current through the cell and the charging current through the double layer capacity are zero, the faradaic current must also be zero. This allows the elimination of both concentration polarization and ohmic drop so that the charge transfer overvoltage is obtained directly. The method, denoted as GRC, is mainly distinguished by very simple analysis of experimental data and good potentialities. In addition it seems to be especially promising for the study of electrode processes where determination of double layer capacity in situ is vital.