Continuous real-time monitoring of hazardous gases is essential for safeguarding public health and environmental integrity, necessitating the utilization of highly selective and sensitive gas sensors. Herein, the chemiresistive sensor for NO was fabricated based on Bi nanoparticles (NPs) doped Mn-porphyrin MOF PCN-222-Mn (Bi@PCN-222-Mn) through a straightforward in situ reduction process. Bi NPs serve as electron donors, facilitating the migration of electrons towards the PCN-222-Mn through the formation of a Schottky barrier caused by electrostatic interaction. Besides the Mn-porphyrin as detecting site in PCN-222-Mn, the Bi NPs in Bi@PCN-222-Mn act as supportive sites, enabling NO adsorption and electron transfer to NO simultaneously, thus enhancing the response signal amplification. Consequently, Bi@PCN-222-Mn exhibited the specific sensing for NO with 5 times higher sensitivity (238.6 % ppm) in the range of 0.05–2 ppm and a lower limit of detection (LOD) (13 ppb) compared to PCN-222-Mn. Moreover, the Bi@PCN-222-Mn-based chemiresistive sensor also exhibited outstanding long-term stability and moisture resistance, applicable for the practical detection of NO. These results prove the feasibility of improvement of gas detection performance by introducing metal NPs as electron mediator and an idea for the application of MOFs in gas sensing.

中文翻译：

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基于Bi电子介体掺杂PCN-222-Mn的NO2高性能特异性检测

持续实时监测有害气体对于保障公众健康和环境完整性至关重要，因此需要使用高选择性和灵敏的气体传感器。在此，通过简单的原位还原过程，基于 Bi 纳米颗粒 (NP) 掺杂的锰卟啉 MOF PCN-222-Mn (Bi@PCN-222-Mn) 制造了 NO 化学电阻传感器。Bi NP 作为电子供体，通过静电相互作用形成肖特基势垒，促进电子向 PCN-222-Mn 迁移。除了PCN-222-Mn中的Mn-卟啉作为检测位点外，Bi@PCN-222-Mn中的Bi NPs还充当支持位点，使NO吸附和电子转移到NO同时，从而增强响应信号放大。因此，与 PCN-222-Mn 相比，Bi@PCN-222-Mn 对 NO 表现出特异性传感，在 0.05-2 ppm 范围内灵敏度高出 5 倍（238.6 % ppm），检测限 (LOD) 更低（13 ppb）。 222-锰。此外，Bi@PCN-222-Mn基化学电阻传感器还表现出出色的长期稳定性和耐湿性，适用于NO的实际检测。这些结果证明了通过引入金属纳米粒子作为电子介体来提高气体检测性能的可行性以及MOFs在气体传感中的应用的想法。