Mixed ionic-electronic conduction of Na-beta-alumina under the conditions of a potentiometric CO2 sensor

It is shown that, on employing a practically relevant type of a potentiometric solid state CO, sensor comprising Na-beta-alumina as solid electrolyte and Na2CO3 as gas sensitive electrode, the voltage response may be remarkably affected by electronic transference. This is in contradiction to what is commonly stated in the literature about the measuring properties of such a type of a sensor. On the other hand, the observation of a non-negligible amount of electronic conduction confirms previous findings on the behaviour of Na-beta-alumina under the conditions of a CO2 sensor.