Zhou Tingting, Sang Yutong, Sun Yanling, Wu Congyi, Wang Xiaoxia, Tang Xing, Zhang Tian, Wang Hao, Xie Changsheng, Zeng Dawen
State Key Laboratory of Materials and Processing Die and Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering , Huazhong University of Science and Technology , No. 1037, Luoyu Road , Wuhan 430074 , China.
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials , Hubei University , Wuhan 430062 , China.
Langmuir. 2019 Mar 5;35(9):3248-3255. doi: 10.1021/acs.langmuir.8b02642. Epub 2019 Feb 21.
The detection of trace amount of volatile organic compounds (VOCs) has been covered by tons of researches, which are dedicated to improve the detection limit and insensitivity to humidity. In this work, we have synthesized ZnO@ZIF-71 nanorod arrays (NRAs) equipped with the adsorption effect at metal site that promoted the detection limit of ethanol and acetone, to which also have great selectivity. The gas sensor not only exhibits shorter response/recovery time (53/55% for ethanol, 48/31% for acetone), but also excellent insensitivity to humidity and improved detection limit (10× improved at 21 ppb for ethanol, 4× at 3 ppb for acetone) at low working temperature (150 °C). By the analysis of in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and calculation of density functional theory (DFT), the mechanism of enhanced gas sensing performance from ZnO@ZIF-71 NRAs is proved. It shows ethanol and acetone gas molecules can be adsorbed at the metal sites of ZIF-71. This work provides a new idea to improve the detection limit and humidity-insensitivity of gas sensor toward specific gas molecules.
痕量挥发性有机化合物（VOCs）的检测已被大量研究报道，这些研究致力于提高检测限以及对湿度的不敏感性。在本工作中，我们合成了具有金属位点吸附作用的ZnO@ZIF-71纳米棒阵列（NRAs），该吸附作用提高了对乙醇和丙酮的检测限，且对这两种气体具有高选择性。该气体传感器不仅具有较短的响应/恢复时间（乙醇为53/55%，丙酮为48/31%），而且在低工作温度（150°C）下对湿度不敏感且检测限有所提高（乙醇在21 ppb时提高了10倍，丙酮在3 ppb时提高了4倍）。通过原位漫反射红外傅里叶变换（DRIFT）光谱分析和密度泛函理论（DFT）计算，证实了ZnO@ZIF-71 NRAs增强气敏性能的机理。结果表明，乙醇和丙酮气体分子可吸附在ZIF-71的金属位点上。本工作为提高气体传感器对特定气体分子的检测限和湿度不敏感性提供了新思路。
