Bi-electrolyte Carbon Dioxide Gas Sensor Based on Paste Sodium-Beta Alumina and Yttria-stabilized Zirconia

Abstract

CO 2 sensor was used only one solid electrolyte in many cases. To improve the sensing characteristics of CO 2 sensors, solid electrolyte CO 2 sensor has been developed by bi-electrolyte type sensor using Na-Beta-alumina and YSZ. However, in many further studies, bielectrolyte type sensor was made by pellet pressed by press machine and additional treatment for formation of interface. In the aspect of mass production, using thick film and additional treatment is not suitable. In this study, CO 2 sensor was fabricated by bi-electrolyte structure which was made by an NBA paste layer deposited on YSZ pellet and fired at 1650 o C for 2 hour. The formation of stable interface between YSZ and NBA were confirmed by SEM image. When the type IV electrochemical cell arrangement represented by CO 2 ,O 2 ,Pt| Li 2 CO 3 -CaCO 3 ||NBA||YSZ|O 2 ,Pt is used to measure the CO 2 concentration in air. This sensor EMF should depend only on the concentration of CO 2 by logarithmic. Also, sensor shows P CO 2 and EMF relationship like nerstian reaction at a temperature of 450 o C.