Strategies for the determination of the convective-diffusion limiting current from steady state linear sweep voltammetry

The limiting current is an important parameter for the characterization of mass transport in electrochemical systems operating under convective-diffusion control. Four methods to determine the limiting current from current (I) vs. potential (E) plots are considered. Strategies to determine the limiting current values include: (1) direct measurement from I vs. E curves, (2) estimation from the current value at E (L) = Delta E/2 where Delta E is the length of the limiting current plateau, (3) evaluation of the first derivative dI/dE in the I vs. E curve and (4) from plots of E/I vs. I (-1). The electrode reactions chosen to demonstrate the different strategies are: Cu(II) -> Cu(I) and Cu(I) -> Cu(0) in 1.5 mol dm(-3) NaCl (pH 2) at a platinum rotating disc electrode and Fr(CN)(6)(3-) -> Fr(CN)(6)(4-) in 1 mol dm(-3) NaOH at a 60 ppi reticulated vitreous carbon electrode (RVC).