Selective Electrocatalytic Hydrogenation of Nitroarenes on Interlayer-Expanded MoS₂

Abstract

As a promising route to hydrogenate organic compounds at ambient conditions, electrocatalytic hydrogenation (ECH) urgently demands noble-metal-free electrocatalysts with satisfactory activity and selectivity. Here, molybdenum disulfide intercalated by dimethylamine (MoS2-DMA) demonstrates its superiority associated with the engineered interlayer chemistry in the ECH of nitroarenes to anilines. The in situ intercalation by DMA cations leads to the phase transition from semiconducting 2H to metallic 1T and the formation of abundant sulfur vacancies, which is beneficial for activating nitro groups and stabilizing chemisorbed H intermediate toward fast hydrogenation. In a wide potential range of −0.08 to −0.48 V (vs reversible hydrogen electrode (RHE)), MoS2-DMA affords the excellent ECH performance of p-nitrostyrene to p-aminostyrene with high Faradic efficiency (>90%), yield (>90%), and selectivity (>99%), outperforming typical MoS2. The good efficiency of such intercalated MoS2 within a broad substrate scope further verifies the promise of interlayer engineering for exploiting cost-efficient catalysts in an electrochemical refinery.

Catalytic and Electrocatalytic Hydrogenation of Nitroarenes

“…In addition, the selectivity of precious metal cathode materials is also one of the factors limiting their application. 9 Other transition metals like Fe, Cu, and Ni are highly abundant but with low activity, poor stability, and corrosion resistance. Cu-based electrodes have been widely used in this electrochemical system.…”

“…And the side reaction consumes the reactive hydrogen adsorbed, which will reduce the Faraday efficiency of the reaction. In addition, the selectivity of precious metal cathode materials is also one of the factors limiting their application . Other transition metals like Fe, Cu, and Ni are highly abundant but with low activity, poor stability, and corrosion resistance.…”

“…Given the current environmental impact and scale of global aromatic amine production, the electrochemical route is expected to develop more sustainable processes for the production of these important chemical feedstocks. Compared with the thermocatalysis hydrogenation technology, electrocatalytic hydrogenation uses safe and nontoxic water molecules as hydrogen donors, so that it could avoid the use of high-pressure hydrogen and improve the safety of the reaction to a certain extent . Meanwhile, it also has the advantages of simple operation, good environmental compatibility, and controllable redox potential.…”

“…Compared with the thermocatalysis hydrogenation technology, electrocatalytic hydrogenation uses safe and nontoxic water molecules as hydrogen donors, so that it could avoid the use of highpressure hydrogen and improve the safety of the reaction to a certain extent. 9 Meanwhile, it also has the advantages of simple operation, good environmental compatibility, and controllable redox potential. However, the electrocatalytic hydrogenation usually requires a continuous three-step two-electron process.…”

Alloying promotion of Pd-based metallenes in electrocatalytic hydrogenation of functionalized nitroarenes

“…8,10,11 Thereinto, electrocatalysts with elaborately designed surface congurations usually play a paramount role in promoting an efficient transformation via target routes. [12][13][14][15] Palladium (Pd)-based electrocatalysts capable of adsorbing/ activating protons and water are highly active for cathodic hydrogenation. [16][17][18][19][20] Unfortunately, they are also active for the hydrogen evolution reaction (HER) that consumes chemisorbed H (H*, * denotes an active site) and reduces the faradaic efficiencies (FEs) of target aniline products.…”