Theory of square-wave voltammogram starting at the equilibrium potential

If both a reactant and product of an electrode reaction are present in the bulk of solution, the square-wave voltammogram can be recorded by starting at the equilibrium potential. If the reaction is reversible, the redox state of investigated substance can be estimated from the ratio of peak currents of the forward and backward components. The degree of reversibility of the reaction can be assessed from the current at the starting potential. Also, the dependence of the logarithm of forward component of irreversible response on the electrode potential can be used for the calculation of transfer coefficient.

► Theory of square-wave voltammogram that starts at the equilibrium potential is developed.
► A method for the estimation of redox state of dissolved compound is described.
► A determination of transfer coefficient by the Tafel plot is demonstrated.