On the Initial EMF Stabilization of the Electrochemical CO2 Sensors

Abstract

Initial EMF stabilization behavior of the electrochemical CO2 sensor based on the galvanic cell, Pt, O-2, CO2, Na2CO3//Na beta-Alumina//Na2Ti6O13-TiO2, O-2, Pt is investigated using electrochemical impedance spectroscopy (EIS) combined with EMF measurement. From the measured impedance spectra variation with time, it is deduced that the continuous increase in EMF at early operation stage is deeply related to the sluggish stabilization process of reference electrode material, Na2Ti6O13-TiO2, adopted in CO2 sensor rather than carbonate sensing electrode which is quickly stabilized. Fast stabilization of reference material of two phase mixture is the key in order to make the electrochemical CO2 sensor applicable for wide range of fields and replacable with NDIR analyzer.