The effect of electrochemical promotion of catalysis on the SO2 oxidation reaction was investigated over thin (similar to 40 nm) Pt catalyst electrodes interfaced with YSZ, in a monolithic electrochemically promoted (MEP) reactor equipped with five or twenty-two electrocatalytic plates. A mildly oxidizing gas mixture was used at temperatures from 330 to 370 degrees C and flowrates between 1 and 30 L min(-1). It was found that positive potential application, i.e. O2- supply to catalyst surface, can cause an increase of up to 200% in the catalytic oxidation rate of SO2 with Faradaic efficiency values up to 30 at flowrates as high as 30 L min(-1) which corresponds to 3 x 10(4) h(-1) space velocity or 0.1 s residence time. The results show the strong potential of MEP reactors for practical applications of the electrochemical promotion of catalysis (EPOC) effect, in gas treatment units and chemical synthesis and destruction processes. (c) 2011 Elsevier B.V. All rights reserved.