Effect of Scan Rate in Cyclic Voltammetry

In a cyclic voltammetry experiment, scanning the potential in both directions provides with the opportunity to explore the electrochemical behavior of species generated at the electrode. This is a distinct advantage of cyclic voltammetry over other voltammetric techniques. The illustration below, for example, shows the cyclic voltammogram for the same redox couple at both a faster (a) and a slower (b) scan rate. At the faster scan rate we see two peaks; however, at the slower scan rate the peak on the reverse scan disappears. One explanation for this is that the slow scan rate allows sufficient time for the products of the reduction of R on the forward scan to participate in a chemical reaction whose products are not electroactive.