Oxygen sensors based on stabilized zirconia electrolyte are in common use to measure and monitor the oxygen partial pressure in numerous industrial and laboratory environments. These sensors usually operate at a temperature between 600 and 1000℃. The high operating temperature is due to the low oxygen ion conductivity of the electrolyte at temperatures lower than 600℃ and also due to slow electrode kinetics.
In order to lower the operating temperature of oxygen sensor based on YSZ(yttria stabilized zirconia) electrolyte, the various high electrocatalytic electrodes were used and EMF behaviors, sensitivity and long-term stability were tested. Among these electrodes silver was showed the best performance.
The lower heat-treatment temperature of Ag working electrode suppressed the formation of silver cluster oxides working as an insulator. Also the sealing structure of this sensor controled the additional formation of silver cluster at Ag reference electrode. These processes finally reduced the impedances of electrodes itself and the interface between electrodes and an electrolyte.
