A novel dismantlable monolithic-type electrochemically promoted catalytic reactor and "smart" sensor-catalytic reactor unit has been constructed and tested for hydrocarbon oxidation and NO reduction by C2H4 in the presence of O-2. In this novel reactor, thin (similar to 40 nm) porous catalyst films made of two different materials are sputter-deposited on opposing surfaces of thin (0.25 mm) parallel solid electrolyte plates supported in the grooves of a ceramic monolithic holder and serve as sensor or electropromoted catalyst elements. The catalyst dispersion was higher than 10%. A 22 flat plate reactor operated with apparent Faradaic efficiency up to 100, at near complete reactants conversion, at gas flow rates up to 30 l/min. The novel design has only two external electrical connections and thus significantly facilitates the practical utilization of electrochemical promotion of catalysis. (c) 2006 Elsevier B.V. All rights reserved.