A Low-Temperature Synthetic Route Toward a High-Entropy 2D Hexernary Transition Metal Dichalcogenide for Hydrogen Evolution Electrocatalysis

Jie Qu; Amr Elgendy; Rongsheng Cai; Mark A Buckingham; Athanasios A Papaderakis; Hugo de Latour; Kerry Hazeldine; George F S Whitehead; Firoz Alam; Charles T Smith; David J Binks; Alex Walton; Jonathan M Skelton; Robert A W Dryfe; Sarah J Haigh; David J Lewis

doi:10.1002/advs.202204488

A Low-Temperature Synthetic Route Toward a High-Entropy 2D Hexernary Transition Metal Dichalcogenide for Hydrogen Evolution Electrocatalysis

Adv Sci (Weinh). 2023 May;10(14):e2204488. doi: 10.1002/advs.202204488. Epub 2023 Mar 23.

Authors

Jie Qu¹, Amr Elgendy², Rongsheng Cai³, Mark A Buckingham¹, Athanasios A Papaderakis², Hugo de Latour³, Kerry Hazeldine⁴, George F S Whitehead⁵, Firoz Alam⁵, Charles T Smith⁶, David J Binks⁶, Alex Walton⁴, Jonathan M Skelton⁵, Robert A W Dryfe², Sarah J Haigh³, David J Lewis¹

Affiliations

¹ Department of Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
² Department of Chemistry and Sir Henry Royce Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
³ Department of Materials, National Graphene Institute and Sir Henry Royce Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
⁴ Department of Chemistry and the Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
⁵ Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
⁶ Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.

Abstract

High-entropy (HE) metal chalcogenides are a class of materials that have great potential in applications such as thermoelectrics and electrocatalysis. Layered 2D transition-metal dichalcogenides (TMDCs) are a sub-class of high entropy metal chalcogenides that have received little attention to date as their preparation currently involves complicated, energy-intensive, or hazardous synthetic steps. To address this, a low-temperature (500 °C) and rapid (1 h) single source precursor approach is successfully adopted to synthesize the hexernary high-entropy metal disulfide (MoWReMnCr)S₂ . (MoWReMnCr)S₂ powders are characterized by powder X-ray diffraction (pXRD) and Raman spectroscopy, which confirmed that the material is comprised predominantly of a hexagonal phase. The surface oxidation states and elemental compositions are studied by X-ray photoelectron spectroscopy (XPS) whilst the bulk morphology and elemental stoichiometry with spatial distribution is determined by scanning electron microscopy (SEM) with elemental mapping information acquired from energy-dispersive X-ray (EDX) spectroscopy. The bulk, layered material is subsequently exfoliated to ultra-thin, several-layer 2D nanosheets by liquid-phase exfoliation (LPE). The resulting few-layer HE (MoWReMnCr)S₂ nanosheets are found to contain a homogeneous elemental distribution of metals at the nanoscale by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) with EDX mapping. Finally, (MoWReMnCr)S₂ is demonstrated as a hydrogen evolution electrocatalyst and compared to 2H-MoS₂ synthesized using the molecular precursor approach. (MoWReMnCr)S₂ with 20% w/w of high-conductivity carbon black displays a low overpotential of 229 mV in 0.5 M H₂ SO₄ to reach a current density of 10 mA cm^-2 , which is much lower than the overpotential of 362 mV for MoS₂ . From density functional theory calculations, it is hypothesised that the enhanced catalytic activity is due to activation of the basal plane upon incorporation of other elements into the 2H-MoS₂ structure, in particular, the first row TMs Cr and Mn.

Keywords: 2D material; high-entropy disulfide; hydrogen evolution reaction electrocatalysis; single source precursor.

Grants and funding

ERC_/European Research Council/International