ELECTRODE REACTION2

"An electrode reaction always occurs in several series and parallel elementary reaction steps. Even in the simplest case there are three steps in series: (1) the reactant must be transported to the electrode surface from the bulk of the electrolyte (usually predominantly by diffusion, but it can also occur by electromigration), (2) a charge-transfer reaction occurs, and (3) the product must be transported from the electrode surface to the bulk of the electrolyte. "