Application of Srβ-alumina solid electrolyte to a CO2 gas sensor

Srβ-alumina was synthesized in a SrO–MgO–Al2O3 system by solid state sintering, and the electrical conductivity was measured at 873–1673 K by impedance spectroscopy. The oxygen concentration cell method was applied to measure the ionic transport number. The ionic transport numbers were close to 1 in the temperature range between 1200 and 1600 K. Open- and closed-type CO2 gas sensors were constructed using the Srβ-alumina solid electrolyte and a Pt–SrCO3 auxiliary electrode. The CO2 sensors responded well to the changes of CO2 partial pressures at temperatures of 1073–1373 K.