Department of Chemistry, NEST Lab., College of Science, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
Mikrochim Acta. 2021 Feb 12;188(3):81. doi: 10.1007/s00604-021-04723-2.
A 2D ultrathin MXene nanosheet was prepared under controlled conditions and employed as a sensitive film to construct a QCM (quartz crystal microbalance) humidity sensor by a dip coating method. The MXene nanosheets were obtained by dislodging the element A from the MAX phase by a facile liquid phase etching method. The morphology and composition of the MXene nanosheets were characterized by means of a number of advanced instruments. It was found that the sample is an ultrathin graphene-like nanosheet. The sensing test results showed that the sensor has a 12.8 Hz/% RH sensitivity, 6 s and 2 s (@ 90%) response/recovery time, maximum humidity hysteresis of 1.16% RH, good stability, and selectivity. Finally, the enhanced humidity response mechanism of the MXene nanosheets was explored by density-functional theory (DFT) calculation and experimental verification. The DFT simulation together with comparison of fluoride-free sample revealed that F elements on the surface of the MXene nanosheets play a more important role in improving humidity responses than OH groups. The results present a new strategy to enhance humidity sensing performance of sensing materials by F doping or decoration. Thus, the sensor has bright potential for humidity sensing.
在受控条件下制备了二维超薄 MXene 纳米片，并通过浸涂法将其用作敏感膜来构建 QCM（石英晶体微天平）湿度传感器。通过简便的液相刻蚀法从 MAX 相中剥落元素 A 来获得 MXene 纳米片。通过多种先进仪器对 MXene 纳米片的形貌和组成进行了表征。结果表明，该样品为超薄类石墨烯纳米片。传感测试结果表明，该传感器具有 12.8 Hz/%RH 的灵敏度、6 s 和 2 s（@90%）的响应/恢复时间、最大湿度滞后 1.16%RH、良好的稳定性和选择性。最后，通过密度泛函理论（DFT）计算和实验验证探讨了 MXene 纳米片增强湿度响应的机制。DFT 模拟以及无氟样品的比较表明，MXene 纳米片表面的 F 元素比 OH 基团在提高湿度响应方面起着更为重要的作用。结果为通过 F 掺杂或修饰来增强感测材料的湿度感测性能提供了新策略。因此，该传感器在湿度感测方面具有广阔的应用前景。
