Functionalization of Liquid-Exfoliated Two-Dimensional 2H-MoS2

Layered two‐dimensional (2D) inorganic transition‐metal dichalchogenides (TMDs) have attracted great interest as a result of their potential application in optoelectronics, catalysis, and medicine. However, methods to functionalize and process such 2D TMDs remain scarce. We have established a facile route towards functionalized layered MoS2. We found that the reaction of liquid‐exfoliated 2D MoS2, with M(OAc)2 salts (M=Ni, Cu, Zn; OAc=acetate) yielded functionalized MoS2–M(OAc)2 materials. Importantly, this method furnished the 2H‐polytype of MoS2 which is a semiconductor. X‐ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT–IR), and thermogravimetric analysis (TGA) provide strong evidence for the coordination of MoS2 surface sulfur atoms to the M(OAc)2 salt. Interestingly, functionalization of 2H‐MoS2 allows for its dispersion/processing in more conventional laboratory solvents. Surface modification: Functionalization of liquid‐exfoliated, defect‐free, layered 2H‐MoS2 was achieved through coordination of metal carboxylate salts by basal‐plane sulfur atoms. The surface‐coordinated metal center acts as an anchor for ligating organic functionalities. X‐ray photoelectron spectroscopy (XPS) provides strong evidence for the coordination of MoS2 surface sulfur atoms to the M(OAc)2 salt (see picture).