Chemically Exfoliated MoS₂ Nanosheets as an Efficient Catalyst for Reduction Reactions in the Aqueous Phase

Abstract

Chemically exfoliated MoS2 (ce-MoS2) nanosheets that incorporate a large fraction of metallic 1T phase have been recently shown to possess a high electrocatalytic activity in the hydrogen evolution reaction, but the potential of this two-dimensional material as a catalyst has otherwise remained mostly uncharted. Here, we demonstrate that ce-MoS2 nanosheets are efficient catalysts for a number of model reduction reactions (namely, those of 4-nitrophenol, 4-nitroaniline, methyl orange, and [Fe(CN)6](3-)) carried out in aqueous medium using NaBH4 as a reductant. The performance of the nanosheets in these reactions is found to be comparable to that of many noble metal-based catalysts. The possible reaction pathways involving ce-MoS2 as a catalyst are also discussed and investigated. Overall, the present results expand the scope of this two-dimensional material as a competitive, inexpensive, and earth-abundant catalyst.

Oxidation suppression during hydrothermal phase reversion allows synthesis of monolayer semiconducting MoS2 in stable aqueous suspension

“…1) at high MoS 2 concentration (∼200 mg L −1 of Mo – see Fig. S1 † ), consistent with prior observations by Guardia et al 21 Although the use of dilute MoS 2 (40 mg L −1 of Mo) suspensions is useful for preventing flocculation, 21 ICP-OES measurements of soluble Mo species show that a large fraction of the MoS 2 nanosheets are destroyed by oxidative dissolution (∼50% at initial loading 40 mg L −1 of Mo) under these dilute conditions (Fig. S1 † ).…”

“…2,19 Also the 1H/2H form is reported to be hydrophobic, 20 leading to instability, flocculation, and restacking in aqueous solutions. Guardia et al 21 successfully maintained colloidal stability by using very dilute nanosheet suspensions, but dilute processing is a disadvantage for high-volume production.…”

“…This communication documents the resulting improved synthesis method, which not only avoids oxidative degradation of the nanosheets and yield loss, but surprisingly also solves the previously observed problem of colloidal instability. 21,27 …”

Hierarchical MoS2 intercalated clay hybrid nanosheets with enhanced catalytic activity

“…Therefore, mono-or fewlayered MoS 2 sheets exhibit higher catalytic activity than bulk MoS 2 , as they have more exposed edges. Various methods have been used to obtain few-layered MoS 2 sheets, such as hydrothermal and solvothermal synthesis, modified liquid exfoliation [13,14], chemical routes, and chemical vapor deposition. However, MoS 2 nanosheets easily aggregate owing to their high surface energy, which results in deteriorated catalytic activity and stability.…”

Emerging Parallel Dual 2D Composites: Natural Clay Mineral Hybridizing MoS2 and Interfacial Structure

“…MoS 2 nanosheets with single layer or few layers exhibit unexpectedly exotic behaviors compared with the bulk MoS 2 . A few new strategies have been developed for the synthesis of MoS 2 nanosheets, such as modifi ed liquid exfoliation, [ 25 ] hydrothermal or solvothermal synthesis, [ 26,27 ] and laser thinning. [ 28 ] However, the MoS 2 nanosheets are easily agglomerated for high surface energy, which leads to serious decrease of the performance.…”