Effect of electrode materials on the response of oxygen sensors and the electrode kinetics

The lowest limit of operation temperature for the solid electrolyte oxygen sensor was significantly reduced by using perovskite-type oxide electrodes and a ceria-based electrolyte. In particular, the sensor with the La0.6Sr0.4Co0.98Ni0.02O3 electrode and (CeO2)0.8(SmO1.5)0.2 electrolyte exhibited theoretical e.m.f. even at 200 °C. The lowest limit of operation temperature of the oxygen sensor was closely related to the cathodic overpotential, the electrode conductivity and the rate of oxygen isotopic exchange reaction.