Aged Zirconia Electrochemical Oxygen Sensor Activation and Re-activation Using NEMCA

Abstract

Zirconia electrochemical oxygen sensor is widely used today in different industrial power and chemicals production applications (O2-Analyzer) and transportation (lambda sensor). Non-Faradaic Electrochemical Modification of Catalytic Activity (NEMCA) was invented in 80th and shown high efficiency in the catalytic activity and selectivity increase of the gas exposed electrodes. For the first time NEMCA was investigated for the activation and re-activation of the industrial potentiometric oxygen sensor based on stabilized zirconia solid electrolyte. Electrochemical promotion of O2-sensors with Pt-cermet electrodes aged in the field was significant with up to 5 times in the sensor’s impedance reduction. Stability tests on the NEMCA activated O2-sensors were showing just a minor impedance increase after 2 weeks. Sensor response time was also reduced using NEMCA by ~5–10 % with up to 3 times the sensor’s signal noise reduction on the aged zirconia oxygen electrochemical cells.