Investigation of the CO oxidation rate oscillations using electrochemical promotion of catalysis over sputtered-Pt films interfaced with YSZ

The oscillatory behaviour of CO oxidation was studied at 250 degrees C and atmospheric pressure using an electrochemical catalyst composed of a thin (60 nm) sputtered-Pt film interfaced with an yttria-stabilized zirconia membrane. Oscillations of CO oxidation rate showed a perfect correlation with those of the electrochemical potential values. Electrochemical promotion of catalysis was used to initiate and stop the oscillatory behaviour. Small current application induced a permanent effect on the oscillatory behaviours. An extremely small negative current (-17 mu A) led to a 4-fold increase of the catalytic activity and created oscillations that were stable even after current interruption. This permanent effect in the oscillatory behaviour of CO oxidation rate is observed for the first time using EPOC. This has been interpreted by the higher tendency of the nanometric-Pt particles to form PtOx in thin sputtered films. (C) 2010 Elsevier B.V. All rights reserved.