Development of hydrogen gas sensors using quartz resonator

The hydrogen gas sensor using quartz resonators is developed to measure less than 4% hydrogen concentration in air. This sensor consists of two quartz resonators. Both sides of electrodes of the sensor resonator are made by platinum thin film. And the reference resonator has Au electrodes. By using this reference resonator, the influence of the temperature and pressure will be canceled. This sensor can measure hydrogen concentration from reaction heat on the platinum catalyst. From experimental results, the frequency of sensor changed linearly in 0% to 5% hydrogen concentrations mixed with the air. The sensor showed 20ppm frequency translation per 1%, and the time constant is about 20 seconds.