Bi electrolyte Carbon Dioxide Gas Sensor

In the quest for improved carbon dioxide (CO2) sensing characteristics, this study focuses on the development of a novel solid electrolyte CO2 sensor utilizing a bi-electrolyte structure constructed from sodium-beta alumina (NBA) and yttria-stabilized zirconia (YSZ). Traditional solid electrolyte CO2 sensors typically utilize a single electrolyte, which may limit their performance. This research overcomes this limitation by fabricating a bi-electrolyte sensor in which an NBA paste layer is deposited on a YSZ pellet and subsequently fired at 1650°C for two hours. The formation of a stable interface between YSZ and NBA is verified through scanning electron microscopy (SEM) imaging. The sensor employs a specific electrochemical cell arrangement to measure CO2 concentration in the air, demonstrating that the electromotive force (EMF) is logarithmically dependent on CO2 concentration. Furthermore, the relationship between partial pressure of CO2 and EMF exhibits Nernstian behavior at 450°C, underscoring the sensor's efficacy. This bi-electrolyte design addresses challenges of mass production by simplifying the fabrication process while improving sensor performance.