Nitrogen dioxide (NO₂) andtriethylamine(TEA) vapor are two typical reactive nitrogen species harmful to personal health and the environment. Thus, multi-functional and reliable sensors were momentous. Herein, the interface engineering of MOF-derived In₂O₃with various contentsof oxygen vacancy (O_V) and different crystalline phases was achieved via pyrolysis of NH₂-MIL-68(In) at different temperatures. High-proportional mixed hexagonal and cubic crystalline phases were presented in the MOF-derived In₂O₃obtained by pyrolysis of NH₂-MIL-68(In) at 400℃ (MOF-In₂O₃-400). Benefiting from the larger surface and interface area, MOF-In₂O₃-400 exhibited abundant O_Vand improved gas-sensing performance compared with the samples obtained at 500℃ and 600℃. Interestingly, the MOF-derived In₂O₃sensors exhibited dual-selective and ppb-level detection of NO₂and TEA vapor at distinct optimum operating temperatures. MOF-In₂O₃-400 exhibited ultra-high response of 1210 to 200 ppb NO₂, and can detect as low as 1 ppb NO₂at 30ºC and TEA vapor as low as 500 ppb at 200ºC. It was also assessed for excellent long-term stability up to 120 days. As a practical demonstration, a prototype device was fabricated on an integrated circuit platform to issue a warning when NO₂or TEA concentrations exceeded the safety thresholds. The results indicate that the MOF-In₂O₃-400 is an excellent candidate in temperature-dependent dual-functional gas sensors towards NO₂and TEA vapor.

原文链接: https://www.sciencedirect.com/science/article/pii/S0925400523012066