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 presence O-2 In this novel reactor, thin (similar to20-40nm) 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. Using Rh/-YSZ/Pt-type catalyst elements, the 22-plate reactor operated with apparent Faradaic efficiency exceeding 25 achieving near complete fuel and NO conversion at 300 degreesC in presence of up to 1.1% O-2 in the feed at gas flow rates exceeding 1.3 l/min. The metal catalyst dispersion was of the order of at least 15%. The novel reactor design requires only two extemal electrical connections and permits easy practical utilization of the electrochemical promotion of catalysis. (C) 2004 Elsevier B.V. All rights reserved.