The Pd-catalyzed NO-CO reaction at temperatures between 320 and 480 degreesC exhibited electrochemical promotion. This reaction was performed in a fuel-cell configuration when Pd is coated on Y2O3-stabilized ZrO2. The electrochemical promotion of the catalytic activity and modification of the selectivity to N2O is reversible and this system showed both electrophilicity and electrophobicity, depending on the direction of oxygen ion pumping. In a typical experiment, the enhancement of reaction rate is 100 times greater than the rate of oxygen ion removal from the catalyst electrode. Rate enhancement, which is defined as the ratio of the reaction rate under electrochemical oxygen removal to the rate under open circuit, of rho (CO2) = 2.2, rho (N2O) = 2.2 and rho (N2) = 4.2 were measured for V-WR = - 1.8 V at 370 degreesC.