General Principles of Electrolysis Reactions

If the solution is unstirred or, as electrochemists term it, quiet, fresh material gets to the electrode only by linear diffusion from the bulk solution to the flat electrode surface. If, however, the solution is flowing past the electrode (or the solution is being stirred or the electrode rotated), the mass transport is a combination of forced convection and diffusion, which is called convective diffusion. 

Let us first examine the quiet solution case, which is depicted at the top of Fig. 1. In the time increment electroactive species from the 

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