使用垂直排列的二维MoS 2纳米膜改善电化学Pb 2+检测,Analytical Chemistry

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使用垂直排列的二维MoS ₂纳米膜改善电化学Pb ²⁺检测
Analytical Chemistry ( IF 6.7 ) Pub Date : 2019-07-23 00:00:00 , DOI: 10.1021/acs.analchem.9b02382
Jae-Hoon Hwang ₁ , Md Ashraful Islam _{2,

3} , Heechae Choi ₄ , Tae-Jun Ko ₂ , Kelsey L. Rodriguez ₁ , Hee-Suk Chung ₅ , Yeonwoong Jung _{2,

3,

6} , Woo Hyoung Lee ₁

Affiliation

MoS ₂纳米膜的最新进展有助于开发重要的与水相关的环境应用。但是，尚未将MoS ₂纳米膜涂层的传感器用于与水有关的环境样品中的重金属检测。在这项研究中，一种新颖的垂直排列的二维（2D）MoS ₂（边缘暴露）纳米膜被应用于原位铅离子（Pb ²⁺）检测。使用方波阳极溶出伏安法（SWASV），在-0.45 V时，与Ag / AgCl相比，开发的传感器在0至20 ppb之间对Pb ²⁺具有极好的线性关系，自来水中的检出限（LOD）改进为0.3 ppb环境。垂直对齐的2D MoS_2个传感器表现出更高的检测灵敏度（比以前的金属[Bi]复合电极高2.8倍），并且对于重复测量（n = 11）具有较低的相对标准偏差，表明Pb ²⁺检测的再现性增强。垂直排列的2D MoS ₂层的灵敏度比水平排列的2D MoS ₂（暴露的基础平面）高2.6倍。密度泛函理论计算表明，Mos ₂侧边缘上的Pb吸附能（4.11 eV）比基面上的Pb吸附能（0.36和0.07 eV）高得多。另外，发现垂直MoS ₂的带隙中心高于Pb ²⁺→Pb还原电位水平，并且能够还原Pb ²⁺。总体而言，新开发的垂直对准2D MoS ₂传感器在可靠的真实饮用水环境中显示出出色的检测Pb ^2+的性能。

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Improving Electrochemical Pb2+ Detection Using a Vertically Aligned 2D MoS2 Nanofilm

Recent advancements in MoS₂ nanofilms have aided in the development for important water-related environmental applications. However, a MoS₂ 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) MoS₂ (edge exposed) nanofilm was applied for in situ lead ion (Pb²⁺) detection. The developed sensor showed an excellent linear relationship toward Pb²⁺ 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 MoS₂ sensor exhibited improved detection sensitivity (2.8 folds greater than a previous metallic [Bi] composite electrode) with lower relative standard deviation for repetitive measurements (n = 11), indicating enhanced reproducibility for Pb²⁺ detection. The vertically aligned 2D MoS₂ layers exhibited 2.6 times higher sensitivity than horizontally aligned 2D MoS₂ (basal plane exposed). Density functional theory calculations demonstrated that adsorption energy of Pb on the MoS₂ 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 MoS₂ was found to be higher than the Pb²⁺ → Pb reduction potential level and capable of reducing Pb²⁺. Overall, the newly developed vertically aligned 2D MoS₂ sensor showed excellent performance for detecting Pb²⁺ in a real drinking water environment with good reliability.

更新日期：2019-07-23

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