Influence of humidity on electrochemical CO2 sensors based on sol-gel processed NASICON with new compositions

Sol-gel processed NASICON-type with new compositions in the Na3Zr2-(x/4)Si2-xP1+xO12 system showed an improved sinterability with an increase in the x value. This is attributed to liquid phase sintering. This dense electrolyte system is suitable for the application as gas sensors. The CO2 gas sensors using highly dense x = 0.667 (sample B) and x = 1.333 (sample C) samples show a stable EMF response in dry atmosphere which is very close to the theoretical value. Although a lower sensitivity and slower response were obtained in humid CO2 gas, the sensor performance recovered after switching from humid gas to dry gas.