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Indexed by:期刊论文

Date of Publication:2018-05-15

Journal:Talanta

Included Journals:PubMed、EI

Volume:182

Page Number:38-48

ISSN No.:1873-3573

Key Words:Cd2+,Electrochemical sensor,Few-layer MoS2 nanosheets,Liquid,Phase exfoliation,Surface functionalization

Abstract:Surface functionalization is an effective strategy in the precise control of electronic surface states of two-dimensional materials for promoting their applications. In this study, based on the strong coordination interaction between the transition-metal centers and N atoms, the surface functionalization of few-layer MoS2 nanosheets was successfully prepared by liquid phase exfoliation method in N, N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone, and formamide. The cytotoxicity of surface-functionalized MoS2 nanosheets was for the first time evaluated by the methylthiazolyldiphenyl-tetrazoliumbromide assays. An electrochemical sensor was constructed based on glass carbon electrode (GCE) modified by MoS2 nanosheets obtained in DMF, which exhibits relatively higher sensitivity to Cd2+ detection and lower cytotoxicity against MCF-7 cells. The mechanisms of surface functionalization and selectively detecting Cd2+ were investigated by density functional theory calculations together with various spectroscopic measurements. It was found that surface-functionalized MoS2 nanosheets could be generated through Mo-N covalent bonds due to the orbital hybridization between the 5 s orbitals of Mo atoms and the 2p orbitals of N atoms of the solvent molecules. The high selectivity of the sensor is attributed to the coordination reaction between Cd2+ and O donor atoms of DMF adsorbed on MoS2 nanosheets. The robust anti-interference is ascribed to the strong binding energy of Cd2+ and O atoms of DMF. Under the optimum conditions, the electrochemical sensor exhibits highly sensitive and selective assaying of Cd2+ with a measured detection limit of 0.2 nM and a linear range from 2 nM to 20 muM. Copyright © 2018 Elsevier B.V. All rights reserved.