CO2/ SOx-sensors with different β“-aluminas as solid electrolytes

Abstract

Abstract. Sensors with solid electrolytes provide the possibility of correct and fast measurements of partial pressures of various gases. By modification of the solid electrolyte, sensors with specific performances may be manufactured.Layers of Na § Li § Ca 2 § and Sl~ § on top of polycrystalline c~-alumina substrates were produced by an in-situ formation process and were used as solid electrolytes for CO2 and SO X sensors. Carbonates and sulphates were applied as measuring electrodes and oxidic mixtures of SiO 2 and silicates were used as reference electrodes. The different performance of these sensors was investigated over a wide temperature range and the results were compared with theoretical data. Different solid electrolyte / electrode combinations were applied, which all showed different characteristic cross sensitivities against water and organic components.

The measurement of dissolved and gaseous carbon dioxide concentration

“…The auxiliary electrolyte has no influence on the cell performance. Different compositions of Nasicon and βalumina were tested successfully [54,56,61]. As observed in our own experiments it seems that Nasicon is less stable against alkali carbonate than β-aluminas.…”

“…After several weeks of operation this time increases tenfold (150 ms) [61]. Solid electrolyte CO 2 sensors using the Ni/carbonate composite as a measuring electrode are suited for measurement of CO 2 in equilibrated water gases [62].…”