https://doi.org/10.1351/goldbook.D01722
A @[email protected] whose magnitude is controlled by the rate at which a reactant in an electrochemical process diffuses toward an electrode-solution @[email protected] (and, sometimes, by the rate at which a product diffuses away from that @[email protected]). For the @[email protected]
D01722.png
there are two common situations in which a @[email protected] current can be observed. In one, the rate of formation of B from electroinactive C is small and the current is governed by the rate of @[email protected] of B toward the electrode surface. In the other, C predominates at equilibrium in the bulk of the solution, but its @[email protected] into B is fast; C diffuses to the vicinity of the electrode surface and is there rapidly converted into B, which is reduced.