Low‐Temperature Operation of Solid Electrolyte Oxygen Sensors Using Perovskite‐Type Oxide Electrodes and Cathodic Reaction Kinetics

Abstract

The lowest limit of operation temperature for the oxide solid electrolyte oxygen sensors was affected by the electrode materials. The sensors with silver and cobalt‐based perovskite‐type oxide electrodes exhibited theoretical EMF's at lower temperatures than those with Pt electrodes. In particular, the sensor with attained theoretical EMF even at 200°C. The electrode materials operative at low temperatures tend to have low cathodic over‐potential. From the kinetic analysis of the exchange current, the rate‐determining step is expected to be the dissociative adsorption of oxygen molecules at high temperatures and the charge transfer process at low temperatures.