Application of Perovskite-Type Oxides to the Sensing Electrode of a LaF₃-Based Oxygen Sensor Workable at Room Temperature

LaF 3 -based oxygen sensors were constructed using six perovskite-type oxides for the sensing electrodes. It was found that oxygen sensing characteristics of the oxide electrodes, i.e., sensitivity to a change in oxygen partial pressure and response time, were greatly dependent on the oxide used, the dependence being closely related with the activity of the oxides for the electrochemical reduction of oxygen in solution. Among the oxides tested, LaCrO 3 , LaCoO 3 and LaMnO 3 were found to yield sensing electrodes with higher sensitivity and shorter response times than Pt sensing electrodes.