General analytical solution for a reversible i/t response to a double potential step at spherical electrodes in the absence/presence of amalgamation effects

Abstract

The general rigorous theory corresponding to double potential step chronoamperometry for a reversible charge transfer reaction in a spherical electrode whose area increases with tz, where z ≥ 0, is presented. The static mercury drop electrode (z = 0) and the dropping mercury electrode (z = 2/3) are addressed specifically. The explicit equations for the current versus time response assuming unequal diffusion coefficients for the oxidized and reduced species are valid when the product is soluble in both the electrolytic solution and the electrode. Comparisons with previous general treatments in the literature are made. The theory is applied to the detection of amalgamation in RP and DNP techniques.Moreover, in this work we show the origin of errors appearing in some general treatments in the literature, these errors lead to physically meaningless results when amalgamation takes place.