Using metal carbonates MCO3 (M = Mg2+, Ca2+, Sr2+ and Ba2+) as Auxiliary Compounds to Prepare the YSZ Based Potentiometric CO2 Sensor

Different insoluble carbonates (MgCO3, CaCO3, SrCO3, BaCO3) were introduced into a base material of Li2CO3-Nd2O3, and the formed ternary compounds worked as an auxiliary sensing material in a potentiometric CO2 sensor. This sensor had YSZ and Au as its solid electrolyte and reference electrode, respectively. By detecting the CO2 response with each as-prepared sensor before and after a water vapour treatment, the characteristics of the auxiliary sensing compounds were considered. Experimental results indicated that the sensor prepared by the BaCO3-Li2CO3-Nd2O3 compound exhibited a stable and reproducible response to CO2 gas over a wide range of 271-576802 ppm. Interestingly, this type of sensor worked well even after a 12-h water vapour treatment at 3 MPa. After further investigations, this sensor may potentially be applied for the practical in situ detection of the CO2 concentration in a combustion exhaust gas atmosphere.