Pd–Pt alloy as a catalyst in gasochromic thin films for hydrogen sensors

We have used Pd–Pt alloy as the catalyst in the hydrogen sensor thin film. Palladium and platinum were co-sputtered on top of a tungsten oxide layer grown by reactive sputtering. Both the sensitivity and the durability were dramatically improved over the case of a palladium single-component catalyst. The fractional change in the optical absorption on exposure to 1% hydrogen gas was increased by a factor larger than 2, and the fractional change decreased only a little after more than 1000 cycles of repeated exposure to 1% hydrogen and air. Moreover, the sensor film exhibited good selectivity to other organic vapors.