The method and app. for carrying out electrochem. promoted catalytic reactions, i.e., catalytic reactions where the catalytic rate and selectivity is modified by applying an elec. current or potential between the porous catalyst film which is deposited on a solid electrolyte and a second catalytic material which is also coated on the other side of the solid electrolyte component. The new app., termed monolithic electropromoted reactor, consists of an appropriately grooved ceramic monolithic casing and of flat or ribbed solid electrolyte plates coated with the appropriate catalysts and support and elec. connections in the parallel grooves carved in the inside walls of the ceramic monolithic reactor casing. The flat of ribbed solid electrolyte plates are parallel to each other and are coated on one side by one catalyst (Catalyst 1) and on the other side by a second catalyst (Catalyst 2). All the catalyst 1 coatings are brought in electronic contact with an electronically conductive coating on one of the inside wall surfaces of the ceramic reactor casing and all the catalyst 2 coatings are brought in electronic contact with a second conductive coating on the opposite wall surface of the ceramic reactor casing. In this way all the electrochem. cells formed one in each plate are elec. connected in parallel and the reactor can be electropromoted by elec. potential or current application at the two terminals. Series elec. connection is also possible via elec. connection of catalyst 2 in each plate with catalyst I in the next plate. [on SciFinder (R)]