Detection of ethanol gas concentration by fuel cell sensors fabricated using a solid polymer electrolyte

Fuel cells using a polymer electrolyte membrane were successfully fabricated and tested for the detection of ethanol gas concentration. Nafion 115 membrane was used for the polymer electrolyte and 10% Pt/C sheets with 0.5 mg/cm2 Pt loading were used as catalyst electrodes. The peak height of electrical signal obtained from the fuel cells was found to be quite linear with the ethanol gas concentration. The electrical signal from the fuel cells was found to show second-order characteristic with respect to the induced voltage from the transient behavior of the response decay. It could be attributed to the diffusion and reaction of ions in the polymer electrolyte, which would be the rate-controlling step among all the steps involved in the fuel cell operation.