THERMODYNAMIC CONDITIONS AT THE INTERFACE BETWEEN NA-BETA-ALUMINA ANDSTABILIZED ZIRCONIA IN A BI-ELECTROLYTE GALVANIC CELL

An analysis of the thermodynamic conditions at the interface between t he two electrolytes was prompted by the criticism found in the literat ure concerning the use of a bi-electrolyte galvanic cell as an advance d CO2 sensor. It turns out that, according to the data for the standar d free enthalpies of formation of the phases involved, a reaction to a thermodynamically more stable compound is unlikely. Even if such a re action took place, the conditions relevant to the electrochemical beha viour of the cell would not be adversely affected. From this point of view the bi-electrolyte cell is without any doubt a promising approach for a smart CO2 sensor. The only aspect that could be a restriction t o the applicability of such a cell is the Na2O enrichment at the inner interface resulting from the electronic transference through both of the electrolytes.