Concentration overpotential is a phenomenon that occurs during electrochemical reactions, wherein the actual potential required to drive a reaction departs from the theoretical value due to concentration gradients of the reactants or products. This deviation is primarily caused by the limited rate at which reactants can diffuse to and products can diffuse away from the electrode surface. In the context of catalysis, understanding and mitigating concentration overpotential is crucial to enhancing the efficiency of catalytic processes.
