Fuel cell sensors with polymer electrolyte membrane for ethanol gas concentration measurement in
human exhaled breath were studied for the purpose of reduction of platinum (Pt) catalyst loading in both
sensor electrodes and decreasing the sensor production cost. The sensors with Nafion electrolyte and different
catalyst loading electrodes including 10, 20, 30, and 40% Pt/C with 0.1, 0.2, 0.25, and 0.3 mg/cm2 Pt
loadings, respectively, were fabricated and tested in this study. The results confirm that the sensor catalyst
loading can be reduced by approximately 130 times compared to the catalyst loading in commercial
sensors without notably changes on the sensor performance. In addition, fabrication of sensors with
very low Pt loading on the cathode side is possible and can be economically favorable for manufacturing
ethanol gas sensors. It also has been shown that the peak current density measurement method, which
expedites the sensor recovering time, can be used for low catalyst loading sensors due to the observation
of very good linearity behavior of the sensor with changing the ethanol gas concentration.