Carbon monoxide sensor for PEM fuel cell systems

Power generation systems based on Proton-exchange membrane (PEM) fuel cells require sensors to detect carbon monoxide to extremely low levels (similar to1 ppm) in the presence of hydrogen and other gaseous components (nitrogen, carbon dioxide, methane and steam). The CO sensors capable of working in reducing environments are almost non-existent. Development of a new CO sensor stable in H-2-rich environment is described. The novel sensing approach is based on the adsorption of CO onto a film of an inorganic material that allows CO detection by monitoring resistance changes of the film in a simulated reformed gas, rich in H-2. When suitable materials were used for the thick film approach, the resistance of the device exhibited a rapid and reversible sensitivity to carbon monoxide in the range 0-5000 ppm over a period of several days, in the presence of hydrogen and nitrogen. (C) 2002 Elsevier Science B.V. All rights reserved.