Covalent functionalization of MoS2nanosheets synthesized by liquid phase exfoliation to construct electrochemical sensors for Cd (II) detection

Xiaorong Gan, Huimin Zhao, Kwok Yin Wong, Dang Yuan Lei, Yaobin Zhang, Xie Quan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

33 Citations (Scopus)

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 MoS2nanosheets was successfully prepared by liquid phase exfoliation method in N, N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone, and formamide. The cytotoxicity of surface-functionalized MoS2nanosheets was for the first time evaluated by the methylthiazolyldiphenyl-tetrazoliumbromide assays. An electrochemical sensor was constructed based on glass carbon electrode (GCE) modified by MoS2nanosheets 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 MoS2nanosheets 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 MoS2nanosheets. 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 μM.
Original languageEnglish
Pages (from-to)38-48
Number of pages11
JournalTalanta
Volume182
DOIs
Publication statusPublished - 15 May 2018

Keywords

  • Cd2+
  • Electrochemical sensor
  • Few-layer MoS2 nanosheets
  • Liquid
  • Phase exfoliation
  • Surface functionalization

ASJC Scopus subject areas

  • Chemistry(all)

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