Cyclic voltammetry in the absence of excess supporting electrolyte: The effect of analyte charge

The cyclic voltammetry of the simple electrochemically reversible reduction, AZA+ne-⇌BZBAZA+ne-⇌BZB, is modelled using numerical simulations. The effect of adding different concentrations of supporting electrolyte is studied as a function of the scan rate, the diffusion coefficients of species A and B and the diffusion coefficients of the ions in the supporting electrolyte. These studies cover the following ZA/ZBZA/ZB redox couples: 2/1, −1/−2, 8/7, and −7/−8. The supporting information contains a table listing the minimum concentration of supporting electrolyte required to achieve fully supported voltammetry pertaining to a range of scan rates (10-1⩽Fνre2DART⩽105); a wide range of charges of the electroactive species (-7⩽ZA⩽8-7⩽ZA⩽8) and includes both one and two electron transfer. This allows experimental conditions to be defined so that any particular Nernstian electrochemical system may be studied under diffusion-only conditions without the need for additional experiments and/or simulations.

► Cyclic voltammetry of the E reduction studied using simulations. ► Minimum support ratio required for diffusional CV varies with several parameters. ► Supporting info contains required support ratios for several A/B couples.