Electrochemical Exfoliation of MoS₂ Crystal for Hydrogen Electrogeneration

Abstract

Transition metal dichalcogenides (TMDs) have recently emerged within the group of 2D materials due to their electrical, catalytic and optical properties significantly enhanced and useful when down-sized to single layer.I n particular,MoS 2 has attracted much attention due to its semiconducting nature with au seful band gap when presenta s single layer,t he enhanced photoluminescence, but also importantly the excellent catalytic properties towards the electrochemical hydrogen evolution. We present heret he preparation of thin layers MoS 2 nanosheetsw ith enhanced catalytic properties towards the hydrogen evolution reaction by meanso fa ne asy and fast electrochemical top-down exfoliation procedurei na queous solution from an aturally occurring MoS 2 crystal. After structurala nd chemical characterization with STEM, AFM, XPS and Raman spectroscopy electrochemicali nvestigationsw ere performed to test catalytic properties in acidic solution for the electrogeneration of hydrogen and compare it to MoS 2 nanosheets obtained through the widelye mployed chemical Li intercalation/exfoliation. Electrochemically exfoliated MoS 2 shows lower Ta fel slope than its counterparto btainedw ithc hemical exfoliation.[a] Dr.A .Ambrosi, Prof. Dr.M .P umera DivisionofChemistry &B iological Chemistry SchoolofP hysical and Mathematical SciencesSupporting information containing STEM images of chemically exfoliated MoS 2 and XPS survey spectra of chemically and electrochemically exfoliated MoS 2 ,and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Recent Advances in Manifold Exfoliated Synthesis of Two‐Dimensional Non‐precious Metal‐Based Nanosheet Electrocatalysts for Water Splitting

“…[ 5–9 ] However, precious metal‐based electrocatalysts are hard to be used in large scale of commercial applications, due to their high costs, poor stability, and low abundance in natural resources. Consequently, numerous low‐cost electrocatalysts based on earth‐abundant elements, such as metal oxides/hydroxides, [ 1,10–16 ] transition metal dichalcogenides (TMDs), [ 2,17–24 ] transition metal carbides and nitrides (TMNs and MXenes), [ 25–32 ] heteroatom‐doped carbons, [ 33–35 ] layered double hydroxides (LDHs), [ 36–38 ] metal–organic frameworks (MOFs), [ 39–42 ] monoelemental catalysts, [ 43–45 ] etc., have been developed to replace noble metal‐based electrocatalysts for water splitting. [ 3,46,47 ]…”

“…Compared to the bottom‐up method, the synthesis strategies of top‐down method are more diverse, including a number of techniques such as guest ions or molecules‐assisted exfoliation, auxiliary force‐assisted exfoliation, electrochemical exfoliation, plasma‐ or pulsed laser‐assisted exfoliation, rapid thermal annealing‐assisted exfoliation, intermediate‐assisted exfoliation, thermal decomposition‐assisted exfoliation, etc. [ 9,15,17,18,25,36,43,52–63 ] In addition to the diversity of synthesis pathway, when faced with some special types of functional 2D materials, such as TMNs used in catalysis, energy storage, superconductivity, etc., [ 64,65 ] the manufacture of its 2D layered structure is very difficult in terms of thermodynamics, [ 66 ] and which own the low stability of thermodynamic and resistance of oxidation under ambient environment. [ 67 ] Therefore, from the perspective of its harsh synthesis conditions, the bottom‐up synthesis method may have a bottleneck in the field of preparation of such 2D materials.…”

Graphene to Advanced MoS2: A Review of Structure, Synthesis, and Optoelectronic Device Application

“…All these methods can be grouped in two major classes of top-down and bottom-up approaches. There are a number of methods for synthesis of 2D materials, as listed in Figure 3a, including: Hummer's method [48], micromechanical cleavage [1,49,50], liquid exfoliation [51] assisted by ion intercalation [52][53][54][55] and mechanical force [47,[56][57][58][59], oxidation assisted liquid exfoliation [17,49,60], chemical vapor deposition [61][62][63][64][65], wet chemical synthesis method [66][67][68][69], electrochemical exfoliation [70][71][72][73][74], ball milling [51,75], etching-assisted exfoliation etc. [76][77][78].…”

High Power Energy Storage via Electrochemically Expanded and Hydrated Manganese-Rich Oxides

“…In this work, we present a scalable "top-down" strategy for the synthesis of EC electrode materials by electrochemically expanding micron-scale high temperature-derived layered manganese-rich oxides. Inspired by the electrochemical exfoliation methods developed for large sheet graphite and MoS 2 , this batch process is significantly quicker than traditional chemical exfoliations and produces expanded bulk particles (Ma et al, 2008;Liu et al, 2014;Achee et al, 2018;Ambrosi and Pumera, 2018). We then show that assembly of the micron-sized expanded materials into electrodes leads to high power capacitive energy storage.…”