Surface concentration nonuniformities resulting from chronoamperometry of a reversible reaction at an ultramicrodisk electrode

• Accurate numerical simulations of chronoamperometry at an UMDE.
• Effect of unequal diffusion coefficients of the redox couple is evaluated.
• Nonuniformities of surface concentrations over the disk are observed.

The chronoamperometric experiment at a disk electrode was simulated, assuming a reversible reaction. When the diffusion coefficients of the two substances involved are different, there appears a surface concentration nonuniformity in the radial direction, exhibiting a maximum effect in time. At long times, the nonuniformity disappears.