Garnet-like solid state electrolyte Li₆BaLa₂Ta ₂O₁₂ based potentiometric CO₂ gas sensor

A new electrochemical cell for CO₂ sensing has been set up using garnet-like solid electrolyte Li₆BaLa₂Ta ₂O₁₂ and Li_0.36WO₃ as a reference electrode. The electromotive force (EMF) of the cell, the reproducibility and the long-term stability of the sensor signals have been examined at temperature between 300 and 500 °C. The EMF was found to be dependent on the partial pressure of CO₂ (pCO₂) and could be expressed by the Nernst equation. The sensitivity of the sensors was 73 mV/decade and 75 mV/decade at 450 and 500 °C, respectively. It was also seen that the sensor showed fast response for CO₂ and the sensor signals was found to be highly reproducible and stable for several days.