Ultra-high-response heat free H2 sensor based on a WO3/Pt-ZnO thin film

Developing linear ultra-high response hydrogen sensors that operate at room temperature without additional heating is paramount for real applications. WO3/Pt-ZnO thin films are fabricated via a two step method. The Pt2+ ions are reduced to metallic Pt0 clusters and co-decorated with WO3 nanoparticles grown on the well-aligned ZnO nanowalls. The H2 response is highly linear and strongly dependent on the metallic Pt0 content. The optimized sample shows a response of 13 and 3870 to 1 ppm and 4000 ppm hydrogen, respectively, with excellent gas selectivity and cycling stability. The microstructure and band energy level analyses indicate that the well-aligned porous nanowall structure and the double charge transport channel enable the ultrahigh hydrogen response.