A fuel-cell-type sensor for detection of carbon monoxide in reformed gases

A solid oxide fuel cell using a samaria-doped ceria electrolyte with a Pd anode was fabricated for detecting carbon monoxide (CO) in reformed gases at 300degreesC. The CO concentration in a flowing mixture of 0-4000 ppm CO 50% hydrogen, 10%, carbon dioxide, and 6% water vapor was related to a decrease in both the electromotive force generated from the cell and the short-circuit current through the cell due to a reversible change in the anodic reaction resistance with the CO concentration. In both signals, the minimum detectable concentration was 50 ppm. and the 90% response and 90% recovery times were as short a., 20 s. (C) 2001 The Electrochemical Society.