Enhanced hydrogen selectivity of thermoelectric gas sensor by modification of platinum catalyst surface

The gas sensing properties of a thermoelectric hydrogen sensor for hydrogen and other flammable gases, methane, ethanol and methanol, were investigated. The signal of the sensor device is the thermoelectric power produced by heat of oxidation of hydrogen on the Pt catalyst on the surface of the thermoelectric thin film of the sensor device. Hexamethyldisiloxane (HMDS) exposure at 1000 ppm and 100 °C decreased the catalytic activity of the thermoelectric gas sensor for hydrogen. However, after the following heat treatment at 200 °C, 2 h, the gas response of the sensor device was recovered and the hydrogen selectivity against methanol gas was enhanced simultaneously.