Stabilized Zirconia Based CO2 Sensors Combined with Carbonate Auxiliary Phase

Abstract
A solid-state electrochemical CO2 sensor was fabricated by combining an MgO-stabilized zirconia (MSZ) tube and Li2CO3 auxiliary phase. The sensor responded very well to 100–1000 ppm CO2 in air at 400–600 °C, with its EMF responses following the Nernst’s equation for the 2-electron reduction of CO2. It was also possible to fabricate an MSZ-based planar-type sensor, which gave stable EMF responses to CO2 regardless of variations in O2 concentration. The CO2 sensing mechanism of these sensors was briefly discussed.