Malepe Lesego, Ndinteh Derek Tantoh, Ndungu Patrick, Mamo Messai Adenew
Department of Chemical Science, University of Johannesburg PO Box 17011, Doornfontein 2028 Johannesburg South Africa
Department of Chemistry, University of Pretoria Private Bag X20, Hatfield 0028 Pretoria South Africa
RSC Adv. 2022 Sep 23;12(42):27094-27108. doi: 10.1039/d2ra04665b. eCollection 2022 Sep 22.
Methanol vapour is harmful to human health if it is inhaled, swallowed, or absorbed through the skin. Solid-state gas sensors are a promising system for the detection of volatile organic compounds, unfortunately, they can have poor gas selectivity, low sensitivity, an inferior limit of detection (LOD), sensitivity towards humidity, and a need to operate at higher temperatures. A novel solid-state gas sensor was assembled using carbon nanoparticles (CNPs), prepared from a simple pyrolysis reaction, and zinc oxide@zeolitic imidazolate framework-8 nanorods (ZnO@ZIF-8 nanorods), synthesised using a hydrothermal method. The nanomaterials were characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy Raman spectroscopy, and Fourier transform infrared spectroscopy. The ZnO@ZIF-8 nanorods were inactive as a sensor, the CNPs showed some sensor activity, and the CNPs/ZnO@ZIF-8 nanorod composite performed as a viable solid-state sensor. The mass ratio of ZnO@ZIF-8 nanorods within the CNPs/ZnO@ZIF-8 nanorod composite was varied to investigate selectivity and sensitivity for the detection of ethanol, 2-propanol, acetone, ethyl acetate, chloroform, and methanol vapours. The assembled sensor composed of the CNPs/ZnO@ZIF-8 nanorod composite with a mass ratio of 1.5 : 6 showed improved gas sensing properties in the detection of methanol vapour with a LOD of 60 ppb. The sensor is insensitive to humidity and the methanol vapour sensitivity was found to be 0.51 Ω ppm when detected at room temperature.
甲醇蒸汽如果被吸入、吞咽或通过皮肤吸收，对人体健康有害。固态气体传感器是检测挥发性有机化合物的一种很有前景的系统，不幸的是，它们可能具有气体选择性差、灵敏度低、检测限（LOD）较差、对湿度敏感以及需要在较高温度下运行等问题。使用通过简单热解反应制备的碳纳米颗粒（CNP）和采用水热法合成的氧化锌@沸石咪唑酯骨架-8纳米棒（ZnO@ZIF-8纳米棒）组装了一种新型固态气体传感器。使用扫描电子显微镜、透射电子显微镜、粉末X射线衍射、X射线光电子能谱、拉曼光谱和傅里叶变换红外光谱对这些纳米材料进行了表征。ZnO@ZIF-8纳米棒作为传感器没有活性，CNP表现出一定的传感器活性，而CNP/ZnO@ZIF-8纳米棒复合材料作为一种可行的固态传感器发挥作用。改变CNP/ZnO@ZIF-8纳米棒复合材料中ZnO@ZIF-8纳米棒的质量比，以研究对乙醇、2-丙醇、丙酮、乙酸乙酯、氯仿和甲醇蒸汽检测的选择性和灵敏度。由质量比为1.5∶6的CNP/ZnO@ZIF-8纳米棒复合材料组成的组装传感器在检测甲醇蒸汽时表现出改善的气敏性能，检测限为60 ppb。该传感器对湿度不敏感，在室温下检测时，甲醇蒸汽灵敏度为0.51Ω ppm。
