Voltammetric mechanistic characterisation of electrode reactions: Distinguishing between chemical instability and fast product diffusion

• E mechanism and ECirre mechanism are simulated.
• The cyclic voltammograms of the two mechanisms can be almost identical.
• The two mechanisms respond similarly to the variation of scan rate.
• Distinguishing the two mechanisms is challenging by cyclic voltammetry alone.

Cyclic voltammetry curves of two kinds of electrode reactions based on a simple E mechanism with unequal diffusion coefficients and the ECirre mechanism under convergent, linear and ‘mixed’ (convergent/linear) diffusion conditions are developed by numerical simulation. We show that these two types of distinct electrode reactions can respond almost identically under cyclic voltammetry and with similar variation with scan rate under mixed and linear diffusion conditions.