Hydrogen-selective thermoelectric gas sensor

A thermoelectric (TE) hydrogen gas sensor was fabricated by depositing a platinum catalyst thin film on the half surface of nickel oxide thick film. When it was exposed to combustible gas diluted by synthetic air, the catalyst layer converts hydrogen and oxygen effectively to water vapor, and give out heat energy, resulting temperature difference across the sensor, and consequently voltage signal. The voltage signal for the 3% H2/air mixture gas at temperature 100 °C, was 4.65 mV while that for 3% CH3OH/air mixture gas was 0.31 mV. The lower detection limit (LDL) of the sensor at 100 °C was lower than 500 ppm, with an excellent linearity of signal voltage to the hydrogen gas concentration.