Interface-engineering in MOF-derived In2O3 for highly sensitive and dual-functional gas sensor towards NO2 and triethylamine

• Published in: Sensors and actuators. B, Chemical Vol. 395; p. 134491
• Main Authors: Han, Jiayin, Kong, Dehao, Zhou, Weirong, Gao, Yubing, Gao, Yuan, Liu, Guannan, Lu, Geyu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2023
• Subjects: Dual selectivity; MOF-derived In2O3; NO2 sensor; Oxygen vacancy; TEA sensor; NO2 sensor; Dual selectivity; MOF-derived In2O3; TEA sensor; Oxygen vacancy
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2023.134491

Nitrogen dioxide (NO2) and triethylamine (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 In2O3 with various contents of oxygen vacancy (OV) 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 In2O3 obtained by pyrolysis of NH2-MIL-68(In) at 400 °C (MOF-In2O3-400). Benefiting from the larger surface and interface area, MOF-In2O3-400 exhibited abundant OV and improved gas-sensing performance compared with the samples obtained at 500 °C and 600 °C. Interestingly, the MOF-derived In2O3 sensors exhibited dual-selective and ppb-level detection of NO2 and 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 NO2 at 30 °C and TEA vapor as low as 500 ppb at 200 °C. 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 NO2 or 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 NO2 and TEA vapor. [Display omitted] •MOF-derived In2O3 with different OV contents were prepared by pyrolysis of NH2-MIL-68(In).•The MOF-derived In2O3 showed temperature-depended dual selectivity for NO2 and TEA.•MOF-In2O3-400 exhibits an ultra-sensitive response of 1210 to 200 ppb NO2 and 128 to 100 ppm TEA.•A sensing prototype is integrated for monitoring and warning of TEA and NO2.•Insight into the mechanism of the synergistic effect in interface-engineering.