Department of Civil, Environmental, and Construction Engineering , University of Central Florida , Orlando , Florida 32816 , United States.
NanoScience Technology Center , University of Central Florida , Orlando , Florida 32826 , United States.
Anal Chem. 2019 Sep 17;91(18):11770-11777. doi: 10.1021/acs.analchem.9b02382. Epub 2019 Jul 31.
Recent advancements in MoS nanofilms have aided in the development for important water-related environmental applications. However, a MoS nanofilm-coated sensor has yet to have been applied for heavy metal detection in water-related environmental samples. In this study, a novel vertically aligned two-dimensional (2D) MoS (edge exposed) nanofilm was applied for lead ion (Pb) detection. The developed sensor showed an excellent linear relationship toward Pb between 0 and 20 ppb at -0.45 V vs Ag/AgCl using square wave anodic stripping voltammetry (SWASV) with the improved limit of detection (LOD) of 0.3 ppb in a tap water environment. The vertically aligned 2D MoS sensor exhibited improved detection sensitivity (2.8 folds greater than a previous metallic [Bi] composite electrode) with lower relative standard deviation for repetitive measurements ( = 11), indicating enhanced reproducibility for Pb detection. The vertically aligned 2D MoS layers exhibited 2.6 times higher sensitivity than horizontally aligned 2D MoS (basal plane exposed). Density functional theory calculations demonstrated that adsorption energy of Pb on the MoS side edge was much higher (4.11 eV) than those on the basal plane (0.36 and 0.07 eV). In addition, the band gap center of vertical MoS was found to be higher than the Pb → Pb reduction potential level and capable of reducing Pb. Overall, the newly developed vertically aligned 2D MoS sensor showed excellent performance for detecting Pb in a real drinking water environment with good reliability.
近年来，MoS 纳米薄膜的进展有助于开发重要的与水有关的环境应用。然而，尚未将 MoS 纳米薄膜涂层传感器应用于与水有关的环境样品中的重金属检测。在这项研究中，一种新型的垂直排列二维（2D）MoS（暴露边缘）纳米薄膜被应用于铅离子（Pb）检测。所开发的传感器在 -0.45 V 对 Ag/AgCl 下，使用方波阳极溶出伏安法（SWASV），在自来水中环境下，对 0 至 20 ppb 的 Pb 表现出优异的线性关系，改进后的检测限（LOD）为 0.3 ppb。垂直排列的 2D MoS 传感器表现出更高的检测灵敏度（比之前的金属[Bi]复合材料电极高 2.8 倍），对重复性测量的相对标准偏差较低（ = 11），表明对 Pb 检测具有增强的重现性。垂直排列的 2D MoS 层的灵敏度比水平排列的 2D MoS（暴露基面）高 2.6 倍。密度泛函理论计算表明，Pb 在 MoS 侧边的吸附能远高于在基面的吸附能（4.11 eV 比 0.36 和 0.07 eV）。此外，还发现垂直 MoS 的能带隙中心高于 Pb → Pb 还原电势水平，并且能够还原 Pb。总体而言，新开发的垂直排列的 2D MoS 传感器在真实饮用水环境中对 Pb 的检测具有出色的性能，可靠性良好。
