A synergistic combination of zinc oxide nanowires array with dual-functional zeolitic imidazolate framework-8 for hybrid nanomaterials-based gas sensors

• Published in: Composites. Part B, Engineering Engineering, 2020-01, Vol.180, p.107552, Article 107552
• Main Authors: Jeon, In Su, Bae, Garam, Jang, Moonjeong, Song, Wooseok, Myung, Sung, Lee, Sun Sook, Jung, Ha-Kyun, Hwang, Jinha, An, Ki-Seok
• Format: Article
• Language: English
• Subjects: A. Hybrid; A. Nano-structures; B. Electrical properties; D. Surface analysis; Gas sensing response
• ISSN: 1359-8368
• DOI: 10.1016/j.compositesb.2019.107552

The complementary hybridization of nanomaterials enables to realize newly synergistic properties, which is a central concept in next-generation widespread applications. In particular, it is well-established that the hybridization of ZnO nanostructure with zeolitic imidazolate framework-8 (ZIF-8) allows the improvement of gas selectivity owing to molecular sieving capability caused by inherently size-defined porous structures of the ZIF-8. Here, we focused on a different viewpoint related with the preconcentration effect of ZIF-8 hybridized with ZnO nanowires (NWs) array on NO2, NH3, and H2 gas response. Hydrothermally-grown, structurally optimized ZnO NWs array are rationally employed for the nucleation sites of ZIF-8 nanocrystals as well as gas sensing channel. The chemical conversion of the surface of ZnO NWs to ZIF-8 was systematically implemented for the formation of core-shell hybrid structure, where morphological features of the ZIF-8 nanocrystals hybridized with the ZnO NWs array were optimized by simply adjusting synthetic conditions. The thickness of encapsulated ZIF-8 could be effectively manipulated by altering the concentration of 2-methylimidazole (HmIM), which strongly affects to determining gas response of ZIF-8@ZnO NWs-based gas sensors because of a variation in gas-loading capabilities related with the preconcentration effect. For the gas sensor based on ZIF-8@ZnO NWs synthesized using 8 mM HmIM solution, the gas response of NO2, NH3, and H2 gases were improved compared to those of the pristine ZnO NWs-based gas sensor. In addition, we consolidated the molecular sieving effect of the ZIF-8 by measuring the gas response of CH4 and C3H8 for suggesting the dual functionality of the hybrid system. •The hybridization of ZnO with zeolitic imidazolate framework-8 (ZIF-8) was implemented.•Morphological features of the ZIF-8 encapsulated in the ZnO NWs were optimized.•The preconcentration and molecular sieving effects of ZIF-8 with ZnO NWs were explored.