A New Highly Selective H2 Sensor Based on TiO2/PtO−Pt Dual-Layer Films

A new highly selective hydrogen sensor based on TiO2/PtO−Pt dual-layer films has been prepared. At 180−200 °C, the prepared nanostructured sensor exhibits an excellent selectivity and good sensitivity to H2 in air but is immune to many other kinds of reductive gases such as CO, NH3, and CH4. The sensor can give a faithful response to 1% H2 in air, while the limitation for detecting H2 in nitrogen is less than 1000 ppm. Influences of operation temperature and humidity on the sensing performance of the sensor were also investigated. The mechanism of the present sensor was attributed to the partial reduction of Ti4+ to Ti3+ by hydrogen catalyzed by a thin film of surface-oxidized Pt nanoparticles.