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

Abstract

A solid oxide fuel cell using a sumaria-doped ceria electrolyte with a Pd anode was fabricated for detecting carbon monoxide (CO) in reformed gases at 300°C. 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-circuits current through the cell due to a reversible change in the anodic 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 as 20 s.