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

A new highly selective hydrogen sensor based on TiO 2 /PtO−Pt dual-layer films has been prepared. At 180−200 °C, the prepared nanostructured sensor exhibits an excellent selectivity and good sensitivity to H 2 in air but is immune to many other kinds of reductive gases such as CO, NH 3, and CH 4 . The sensor can give a faithful response to 1% H 2 in air, while the limitation for detecting H 2 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 Ti 4+ to Ti 3+ by hydrogen catalyzed by a thin film of surface-oxidized Pt nanoparticles.