Surprising Effect of Uncompensated Resistance on the Cyclic Voltammetric Responses for a Reversible Surface-Confined and Uniformly Accessible Redox Couple

A traditional diagnostic for cyclic voltammetric responses is the plot of the peak current i(peak) vs the scan rate vertical bar v vertical bar or vs vertical bar v vertical bar(1/2). For a reversible redox couple with redox moieties freely diffusing in bulk solution, a plot of i(peak) vs vertical bar v vertical bar(1/2) will be linear; for a surface-confined and uniformly accessible reversible couple, a plot of i(peak) vs vertical bar v vertical bar will be linear; however, if there is significant uncompensated resistance, it is the plot of i(peak) vs vertical bar v vertical bar(1/2) that will be linear even if the redox species are surface confined. The present work offers a theoretical basis for this result.