Surface Molecular Separator for Selective Gas Sensing
2020
Choi, Pil Gyu | Liu, Zheng | Hara, Nobuo | Masuda, Yoshitake
A zeolitic imidazolate framework-8 (ZIF-8) layer was introduced as a surface molecular separator to grant the selective gas-sensing ability to thin-film sensor material composed of SnO₂ nanosheets. ZIF-8 possesses a molecular sieving ability, which is in the range of approximately 4.0–4.2 Å. Compared to a SnO₂ nanosheet gas sensor, a ZIF-8/SnO₂ nanosheet gas sensor exhibited a decreased sensor signal response when the gas molecular sizes were large, e.g., C₃H₆ (4.120 Å), 1-C₄H₈ (5.430 Å), and C₉H₁₈O (12.011 Å). However, the ZIF-8/SnO₂ nanosheet sensor signal response to smaller-sized gas molecules, such as C₂H₄ (3.058 Å), was slightly increased due to electron transfer at the ZIF-8 and SnO₂ interface. Therefore, the control of gas selectivity based on molecular size was realized by introducing ZIF-8 as a surface molecular separator. These results pave the way for selective gas sensing in various types of applications that depend on gas selectivity.
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