Aging and Heat-treatment of Room-temperature Hydrogen Sensitive Pt-WO₃ Composite Nanoceramics

Abstract Pt-WO 3 composite nanoceramic produced by pressed and sintered with 5 wt% Pt and WO 3 nanoparticles has a response multiple of about 80 for 800 ppm H 2 -20% O 2 -N 2 and a response multiple of about 10 for 100 ppm H 2 -20% O 2 -N 2 at room temperature of 40 relative humidity(RH), showing an impressive sensing capacity for low concentration hydrogen. However, Pt-WO 3 composite nanoceramic will show the aging phenomenon mainly with the rapid decline of recovery rate in the open air, which limits its application in practical equipment. Fortunately, Pt-WO 3 composite nanoceramic can be reactivated by heat treatment at 200°C for 1 h, thus restoring its pre-aging hydrogen sensitivity capacity. This may be because heat treatment refixed some weak-bonds Pt particles to the original site.