An ultra-fast, ultra-sensitive hydrogen sensor can detect hundreds of parts per million levels of the gas within 60 seconds at room temperature. Researchers from the Korea Advanced Institute of Science and Technology (KAIST) and the University of California-Irvine developed the device with a palladium nanowire array coated with a metal-organic framework that can detect hydrogen.
The researchers coated lithographically patterned Pd nanowires with a zinc-based zeolite imidazole framework (ZIF-8) layer composed of Zn ions and organic ligands. ZIF-8 film is easily applied to Pd nanowires by dipping in a methanol solution, including zinc nitrate hexahydrate and 2-methylimidazole.
Thus, the ZIF-8 filter on the nanowires allows the predominant penetration of hydrogen molecules while screening out larger molecules. The method results in Pd-based sensors with a 20-fold faster recovery and response speed compared to non-coated Pd nanowires at room temperature.
As the device detects hydrogen gas levels under 1 vol% in less than seven seconds, it should be useful in preventing explosions caused by hydrogen gas leaks.