Step 1 (α = 0.5) accounts for most (78%) of the total linearized charge-transfer resistance compared, even though 𝐼 0,2 < 𝐼 0,1 . For Step 2, 𝑅 𝑐𝑡 ′ also begins decreasing at a lower current density than for Step 1, so 𝑅 𝑐𝑡,2 ′ becomes negligible compared to 𝑅 𝑐𝑡,1 ′ at high current densities. However, since the exchange current between the two steps is similar, the overall resistance versus current density relation is not significantly different between the one-step and two-step BV models. In such a case, a one-step BV model may be a reasonable approximation. Overall, the O-GEIS data clearly fit the predicted relationship between differential charge-transfer resistance and current density for BV kinetics, but the data appear to be more consistent with a two-step reaction with α1 = 0.5 and α2 = 3, than with a one-step reaction with α ≈ 0.46.