Use of NASICON/Na2CO3 system for measuring CO2

The detection of CO2 gas at several temperatures using NASICON as a solid e lectrolyte interacting with Na2CO3 or Na2CO3-BaCO3 mixtures has been demons trated previously. Further work has shown that although the detection of CO 2 is possible, with a pseudo-Nernstian response, the values of the slope an d the constant in the emf versus logP(CO2), equation were not always the sa me as those expected by the theory. The results also suggest that the prese nce of oxygen in the gas mixture may affect the response of the sensor. Oth er effects, as the decomposition of Na2CO3 and the formation of Na2O in the surface of NASICON should also be considered. (C) 2000 Published by Elsevi er Science B.V.