Ionic strength induced electrodeposition of two-dimensional layered MoS2 nanosheets. (September 2017)

• Record Type: Journal Article
• Authors: Rastogi, Pankaj Kumar; Sarkar, Sujoy; Mandler, Daniel
• Is Part Of: Applied materials today. Volume 8(2017)
• Page Start: 44
• Page End: 53
• Publication Date: 2017-09
• Subjects: Transition metal dichalcogenides -- MoS2 -- Electrodeposition -- Ionic strength -- HER -- 2D materials; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2017.04.004
• Languages: English
• ISSNs: 2352-9407

Abstract

Graphical abstract: From "nano to nano": electrochemical deposition of 2D nanomaterials from their dispersion by increasing the ionic strength electrochemically. Highlights: We have developed a method for the facile electrochemical deposition of MoS2 from its nano dispersion. The film that is formed on a copper electrode maintains the nanoparticulate structure and properties of the dispersion nanoparticles. There is no redox process that the MoS2 undergoes. Deposition is driven by changing the environment of the MoS2 nanoparticles causing them to irreversible aggregate. Full characterization of the electrochemical deposition process as well as the deposit is provided. Abstract: A new redox-free electrochemical approach for driving the deposition of two-dimensional (2D) layered MoS2 nanosheets is described. First, poly(acylic acid) (PAA) functionalized layered MoS2 nanosheets (PAA-MoS2 ) is prepared to form a stable aqueous PAA-MoS2 dispersion, which is subsequently used for the electrochemical deposition. In contrast to previous electrodeposition methods of MoS2, which involve the redox of molecular precursors of Mo and S, herein we introduce an electrochemical approach for the deposition of 2D layered MoS2 nanosheets directly from their nanometric building blocks, namely from their aqueous dispersion. This "nano to nano" approach is based on altering the ionic strength at the vicinity of the electrode surface by applying a potential. Specifically, the electrogeneration of Cu 2+ ions, cause the PAA-MoS2 nanosheets in the dispersion to aggregate and deposit on the copper electrode. Scanning electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy analysis show clearly that the deposited layered MoS2 maintains its original structure. Furthermore, the electrodeposited PAA-MoS2 nanosheets on copper show excellent catalytic activity for the hydrogen evolution reaction with low overpotential. Hence, we believe that these findings could lead to a generic approach for the formation of thin films or patterns of 2D nanomaterials.