Accelerating Palladium Nanowire H2 Sensors Using Engineered Nanofiltration
| Autor: | Il-Doo Kim, Alana F. Ogata, Reginald M. Penner, Ji-Soo Jang, Shaopeng Qiao, Vivian T. Chen, Won-Tae Koo, Gaurav Jha |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Hydrogen Inorganic chemistry General Engineering Nanowire General Physics and Astronomy chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Oxygen 0104 chemical sciences Membrane Chemical engineering chemistry Gaseous diffusion General Materials Science Metal-organic framework 0210 nano-technology Kinetic diameter Palladium |
| Zdroj: | ACS Nano. 11:9276-9285 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/acsnano.7b04529 |
| Popis: | The oxygen, O2, in air interferes with the detection of H2 by palladium (Pd)-based H2 sensors, including Pd nanowires (NWs), depressing the sensitivity and retarding the response/recovery speed in air-relative to N2 or Ar. Here, we describe the preparation of H2 sensors in which a nanofiltration layer consisting of a Zn metal-organic framework (MOF) is assembled onto Pd NWs. Polyhedron particles of Zn-based zeolite imidazole framework (ZIF-8) were synthesized on lithographically patterned Pd NWs, leading to the creation of ZIF-8/Pd NW bilayered H2 sensors. The ZIF-8 filter has many micropores (0.34 nm for gas diffusion) which allows for the predominant penetration of hydrogen molecules with a kinetic diameter of 0.289 nm, whereas relatively larger gas molecules including oxygen (0.345 nm) and nitrogen (0.364 nm) in air are effectively screened, resulting in superior hydrogen sensing properties. Very importantly, the Pd NWs filtered by ZIF-8 membrane (Pd NWs@ZIF-8) reduced the H2 response amplitude slightly (ΔR/R0 = 3.5% to 1% of H2 versus 5.9% for Pd NWs) and showed 20-fold faster recovery (7 s to 1% of H2) and response (10 s to 1% of H2) speed compared to that of pristine Pd NWs (164 s for response and 229 s for recovery to 1% of H2). These outstanding results, which are mainly attributed to the molecular sieving and acceleration effect of ZIF-8 covered on Pd NWs, rank highest in H2 sensing speed among room-temperature Pd-based H2 sensors. |
| Databáze: | OpenAIRE |
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