The electrochemical promotion of catalysis (EPOC), also known as non-Faradaic
electrochemical modification of catalytic activity (NEMCA), is a rather general phenomenon
observed in about 30 years ago. This phenomenon has a strong impact on modern
electrochemistry, heterogeneous catalysis and surface science. The EPOC effect can be
achieved with porous thin film electrodes interfaced to solid electrolytes. A dramatic
improvement in the catalytic activity has been obtained by polarization of the interface via an
electrical current or potential application. It has been studied for more than 100 catalytic
reactions, including oxidations, reductions and isomerisations and using a variety of metal or
metal oxide catalysts, and different types of solid electrolytes. In this review paper the main
features and mechanisms of the electrochemical promotion effect are summarized and
discussed.