) carries the value of ∝. Eq. 2 enables the determination of: (i) the current density in the kinetically controlled regime, usually obtained at a relatively low activation overpotential and representing the intrinsic reaction rate of the electrocatalyst, and (ii) the contribution of the diffusive mass transport limitations for reactants hindered by low solubility and availability, often obtained at higher overpotentials. This introduces nonlinearity of the log(J)-V response. Here, the rate of reaction becomes so fast that it is no longer limited by its kinetics. The rate coefficient is so large that the reaction cannot actually proceed at this rate because reactants cannot diffusion fast enough to the reaction site. The latter is found in the limiting current (𝑗 𝑙𝑖𝑚 ) region as described by Eq. 3: