Solid Reference Electrode of SO₂ Sensor Using β-Alumina Solid Electrolyte

抄録

The present study was undertaken to find any available solid reference electrode for SO₂ sensor employing β-alumina solid electrolyte. We proposed two reference electrodes, Au+Au₂Na and (β+β″)-alumina, for such a sensor.
Emf measurements of the following cells were performed to investigate the characteristics of the two sodium reference electrodes:
Mo, Na(l) / β″-alumina / Au+Au₂Na(s), Mo
Pt, Au+Au₂Na(s) / β″-alumina / SO₂+SO₃+O₂, Pt
Pt, (β+β″)-alumina in air / β″-alumina / SO₂+SO₃+O₂, Pt
The results indicate that constant sodium activities in these reference electrodes are maintained for a long duration of the experiment. It is concluded that the use of Au+Au₂Na and(β+β″)-alumina reference electrodes is recommended for the SO₂ sensor employing β″-alumina, β-alumina or other sodium ion solid electrolytes.