Gas Sensing Interfaces Of Solid Electrolyte Based Carbon Dioxide Sensors Attached With Metal Carbonate

SUMMARY The solid electrolyte CO2 sensor which combines a NASICON based electrochemical cell with a metal carbonate auxiliary phase is shown to have two gas-sensitive interfaces, i.e., NASICON/sensing electrode (02-sensitive) and carbonatehensing electrode (CO2-sensitive). The latter interface dominates EMF of the device in the high temperature region, providing the device with CO2 sensing capability. In the lower temperature region the former interface dominates, resulting in a complete loss of CO2 sensitivity. The use of a binary carbonate auxiliary phase can effectively extend the lower temperature limit for CO;! sensing operation.