Response Characteristics of Fuel Cell Type Alcohol Sensor Using Nafion Membrane

Abstract

The fuel-cell-type alcohol sensor for commercial use had a separator soaked with sulfuric acid. However, the durability of the sensor was short due to the leakage of sulfuric acid. In this study, we used a polymer electrolyte membrane, a Nafion membrane, instead of the liquid electrolyte for fabricating fuel cell sensors for ethanol. Platinum-based membrane-electrode assemblies have been prepared to do electrochemical measurements of breath alcohol levels. The composition of the fuel used in the experiments was of air, water and ethanol. The range of the ethanol gas concentration was from 0 to 300 ppm. The purpose of this study was to evaluate the transient responses of the cell current of the Nafion-type sensor using various amounts of Pt/C and Pt black catalysts and different membranes at room temperature. The relationships between the amounts of catalyst and peak current density, and the coulomb amount were evaluated. Total amounts of coulomb of transient sensor output were found to be quite linear relative to the ethanol gas concentration. The major reaction products of ethanol oxidation reaction (EOR) were analyzed by mass spectrometer, as acetaldehyde and acetic acid for Pt/C and Pt black catalyst, respective.