†Chair of Organic Chemistry II and Institute of Advanced Materials and Processes (ZMP), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestraße 42, 91054 Erlangen, Germany.
‡Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
ACS Nano. 2015 Jun 23;9(6):6018-30. doi: 10.1021/acsnano.5b00965. Epub 2015 May 20.
Although transition metal dichalcogenides such as MoS2 have been recognized as highly potent two-dimensional nanomaterials, general methods to chemically functionalize them are scarce. Herein, we demonstrate a functionalization route that results in organic groups bonded to the MoS2 surface via covalent C-S bonds. This is based on lithium intercalation, chemical exfoliation and subsequent quenching of the negative charges residing on the MoS2 by electrophiles such as diazonium salts. Typical degrees of functionalization are 10-20 atom % and are potentially tunable by the choice of intercalation conditions. Significantly, no further defects are introduced, and annealing at 350 °C restores the pristine 2H-MoS2. We show that, unlike both chemically exfoliated and pristine MoS2, the functionalized MoS2 is very well dispersible in anisole, confirming a significant modification of the surface properties by functionalization. DFT calculations show that the grafting of the functional group to the sulfur atoms of (charged) MoS2 is energetically favorable and that S-C bonds are formed.
虽然过渡金属二硫属化物（如 MoS2）已被认为是高效的二维纳米材料，但对其进行化学功能化的一般方法却很少。在此，我们展示了一种通过共价 C-S 键将有机基团键合到 MoS2 表面的功能化途径。该方法基于锂离子插层、化学剥离以及随后用亲电试剂（如重氮盐）猝灭存在于 MoS2 上的负电荷。典型的功能化程度为 10-20 原子%，通过选择插层条件可以进行潜在调节。重要的是，没有引入进一步的缺陷，并且在 350°C 退火可以恢复原始的 2H-MoS2。我们表明，与化学剥离和原始 MoS2 不同，功能化的 MoS2 在茴香醚中具有很好的分散性，这证实了表面性质的显著修饰。密度泛函理论（DFT）计算表明，将官能团接枝到（带电的）MoS2 的硫原子上是能量有利的，并且形成了 S-C 键。
