The electrochemical promotion of catalysis (EPOC) of propene combustion was investigated using Pt sputtered thin film on an O2- conductor, 8 mol% Y2O3-stabilized-ZrO2 (YSZ). In order to separate the influence of the thermal migration of the O2- oxide ions from the electrolyte to the catalyst surface and the impact of an electrical polarization on the catalytic activity, several light-off experiments (cool down and heat up procedures) were successively performed under different polarizations, i.e. OCV, +2 and -2 V. These experiments have clearly shown that the presence of O2- (thermally or electrochemically induced) inhibits the catalytic activity of the platinum for the propene deep oxidation. These results demonstrate the importance to define a normalized rate enhancement ratio, rho(n) , from a reference value of the catalytic rate corresponding to a Pt surface state free of O2- ions.