Room-temperature resistive H₂ sensing response of Pd/WO₃ nanocluster-based highly porous film.

Hydrogen- (H₂-) induced resistive response of palladium (Pd) coated tungsten oxide (WO₃) films prepared by using supersonic cluster beam deposition (SCBD) was investigated. An SCBD WO₃ film is found to be constructed of WO₃ nanoclusters of diameters of 3-5 nm. The nanoclusters are loosely connected to form a structure of high porosity around 66%. With this structure, the film exhibits many excellent room-temperature H₂ sensing properties, including high sensitivity, broad detectable range of H₂ concentration, low detection limit, fast response rate, excellent cyclic stability (>2400 cycles), high selectivity against vapor of many organic compounds, mild ambient pressure dependence and many other advantages such as low power consumption, miniaturizability and high batch-to-batch reproducibility. These findings are useful for making new high-quality H₂ sensors for monitoring the leakage of H₂ and ensuring safe use of this gas.