Detection of carbon monoxide by using zirconia oxygen sensor

Abstract An oxygen concentration cell of the type O 2 (1), CO, Pt/stabilized zirconia, YSZ, / Pt, O 2 (2) was found to be sensitive to a small amount of CO in an O 2 -containing gas stream. Electrochemical measurements were carried out for the steady-state polarization curves in the temperature range of 500–650 °C. When CO coexisted in a stream, variation in polarization current was observed in the region within $ = ± 50 mV of the equilibrium potential below 550 °C. In particular, the sensor showed good CO sensing characteristics in the concentration range of 32–800 ppm of CO in air. The CO sensing mechanism of the cell was also discussed.