Abstract
Solid-state potentiometric CO 2 sensors have been fabricated by combining a fluoride-ion conductor (LaF 3) or an oxide-ion conductor (stabilized zirconia) with an auxiliary phase of a metal carbonate (Li 2CO 3). The e.m.f. response of the LaF 3-based sensor fitted with Li 2CO 3 is found to follow Nernst's equation for the two-electron reaction of CO 2 in the concentration range 40–2000 ppm at 400 and 450 °C. The 90% response times are as short as 10–20 s at 400 °C. The tubular-type MgO-stabilized zirconia (MSZ) sensor fitted with Li 2CO 3 also responds well to CO 2, giving the same Nernstian behaviour as above at 500–650 °C. The CO 2 sensitivity of this sensor is hardly affected by coexistent NO, NO 2 or H 2O, and is rather stable for the test period of ≈ 2800 h. Furthermore, it is possible to design a planar-type MSZ sensor that is insensitive to O 2 and gives a stable e.m.f. response to CO 2 regardless of variations in O 2 concentration. The CO 2 sensing mechanisms of these new type sensors are discussed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
