Comparison of solid metal–metal oxide reference electrodes for potentiometric oxygen sensors in liquid lead–bismuth eutectic operating at low temperature ranges

Abstract

Potentiometric oxygen sensors with metal–metal oxide reference electrodes including Cu/Cu2O, Ni/NiO and Fe/Fe3O4 were tested in oxygen saturated lead–bismuth eutectic (LBE) over the temperature range from 200 to 450°C to assess their minimum operating temperature limit. The performance of sensors with the three reference electrodes was compared to that of a sensor with air/lanthanum strontium manganese oxide (LSM) reference electrode using the same solid electrolyte material and measurement setup. The sensor with Cu/Cu2O reference electrode performed well down to 200°C in oxygen saturated LBE, while those with Ni/NiO and Fe/Fe3O4 showed significant deviations from expected values below 300°C. Furthermore, the sensor with Cu/Cu2O electrode showed a response to temperature variations as fast as that of the air/LSM electrode over the entire temperature range of interest in liquid LBE.