Carbon dioxide gas sensor with multivalent cation conducting solid electrolytes

A compact carbon dioxide gas sensor is fabricated by using the trivalent (M 3+: M = Al, SC) cation conducting solid electrolyte with an oxide anion con ducting stabilized zirconia and lithium carbonate as an auxiliary electrode . The response time which is defined as the time to attain a 90% response i s less than several minutes. The sensor output variation with the CO2 conce ntration shows a clear 1 to 1 relation and obeys the theoretical Nernst rel ation. The present sensor can detect the CO2 gas concentration accurately e ven in the atmosphere where nitrogen oxides and water vapor coexist. The re sponse is rapid, continuous, and also reproducible and the performance sati sfies the need for practical applications. (C) 2001 Elsevier Science B.V. A ll rights reserved.