Development of Methanol Sensor Using SH-SAW Sensor for Direct Methanol Fuel Cell

A methanol sensor for direct methanol fuel cell (DMFC) is required. A shear horizontal surface acoustic wave (SH-SAW) sensor for electrical property detection is applied for it. The operative temperature of DMFC is above 50degC. The wave propagation characteristics are calculated with considering temperature coefficient. The results indicate that the sensitivity increases with the temperature. Methanol solutions are measured using the SH-SAW sensor. Linear relationships between the sensor response and concentration were obtained. Also, the increase of the sensitivity is experimentally confirmed. As a formic acid is produced in DMFC, mixture solutions of methanol and formic acid were measured. Using coordinate transformation, it is possible to estimate methanol concentration in mixture solution.