Carbon dioxide gas sensing with the combination of trivalent Sc3+ ion conducting Sc-2(WO4)(3) and O2- ion conducting stabilized zirconia solid electrolytes

A compact carbon dioxide gas sensor was fabricated by applying a trivalent Sc3+ cation conducting Sc-2(WO4)(3) solid electrolyte and an oxide anion co nducting stabilized zirconia with Li2CO3 as an auxiliary electrode. The com bination of an oxide ion conductor which covers one of the trivalent ion co nducting Sc-2(WO4)(3) solid surfaces is greatly effective for obtaining a s table output response. The time necessary for a 90% response was within sev eral minutes, and the response exactly coincided with the theoretical Nerns tian equation, and a 1:1 linear relation was observed between the sensor ou tput and the logarithm of the carbon dioxide gas concentration. Quantitativ e CO2 gas monitoring was successfully realized with a rapid, continuous, re producible and selective response with a long-term stability. (C) 2000 Else vier Science B.V. All rights reserved.