Electrode surface:

Electrode products can often build up on the surface of a solid or stationary electrode. Species from the solution may adsorb on the surface. Some solid electrode materials may even develop oxide layers on the surface. All of these produce changes in the nature of the electrode and often completely distort the electrochemical response. By regular polishing back to a clean metal or graphite surface, some attempt can be made to achieve a reproducible surface. Better results are usually obtained from a smooth rather than a rough surface.