Green synthesis of ultrathin WS2 nanosheets for efficient hydrogen evolution reaction

Nadeesha L. Kothalawala; Nipun Chandrasiri; Manisha De Alwis Goonatilleke; Keerthan R. Rao; Sujan Shrestha; Udari S. Kodithuwakku; Irene Y. Kim; Chad Risko; Ambrose Seo; Beth S. Guiton; Fuqian Yang; Doo Young Kim

doi:10.1039/d5ra00712g

Green synthesis of ultrathin WS₂ nanosheets for efficient hydrogen evolution reaction

Nadeesha L. Kothalawala, Nipun Chandrasiri, Manisha De Alwis Goonatilleke, Keerthan R. Rao, Sujan Shrestha, Udari S. Kodithuwakku, Irene Y. Kim, Chad Risko, Ambrose Seo, Beth S. Guiton, Fuqian Yang, Doo Young Kim

Research output: Contribution to journal › Article › peer-review

Abstract

Transition metal dichalcogenide (TMD) nanostructures have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) as there is an increasing demand for cost-effective and sustainable hydrogen production. Despite significant progress, there is still a critical need for developing facile and green methods for synthesizing ultrathin TMD nanostructures. In this study, we introduce a green, top-down synthesis method to produce highly exfoliated WS₂ nanosheets. The process combines the ultrasonication of bulk WS₂ in a binary water-ethanol solvent with a solvothermal treatment. The resulting ultrathin WS₂ nanosheets exhibit clean surfaces free of surface ligands and impurities, high crystallinity in the semiconducting hexagonal phase, and outstanding electrochemical activity for HER. Key performance metrics include a low onset potential of −0.32 V (vs. reversible hydrogen electrode (RHE)) at 10 mA cm⁻² and a low Tafel slope of 160 mV dec⁻¹ with a catalyst loading of 0.76 mg cm⁻². The promising HER performance is attributed to (1) a high density of exposed edges and defects, (2) enhanced charge transport due to high crystallinity, and (3) clean surfaces enabling efficient interfacial electron transfer. Furthermore, operando Raman spectroscopy using a 3D-printed electrochemical cell identifies the catalytically active sites on WS₂ nanosheets for HER. This work provides a green route to high-performance, low-dimensional electrocatalysts for sustainable hydrogen production.

Original language	English
Pages (from-to)	19305-19317
Number of pages	13
Journal	RSC Advances
Volume	15
Issue number	24
DOIs	https://doi.org/10.1039/d5ra00712g
State	Published - Jun 9 2025

Bibliographical note

Publisher Copyright:
© 2025 The Royal Society of Chemistry.

Funding

This work was supported by the National Science Foundation under OIA 2327349 (DYK, NC) and CBET 2018411 (FY, NLK), and partially by the donors of ACS Petroleum research Fund under New Directions Grant 67748-ND10 (DYK, NC). Partial salary support was provided by Southern company (NLK), the University of Kentucky College of Arts and Sciences (NLK, NC), and the U.S. Department of Energy under DE-SC0022315 (MDAG, BSG). BSG thanks the University of Kentucky's Frank J. Derbyshire Professorship. KRR and CR acknowledge funding by the Research Corporation for Science Advancement (RCSA) Cottrell Scholars program (Award No. 24432). SS and AS acknowledge the support of the National Science Foundation (grant no. DMR-2104296). High-resolution STEM imaging was conducted by Dr Matthew Boebinger at the Center for Nanophase Materials Sciences (CNMS), Oak Ridge National Laboratory which is a DOE Office of Science user facility. TEM and EDS characterization was performed at the Electron Microscopy Center (EMC), University of Kentucky, which belongs to the National Science Foundation NNCI Kentucky Multiscale Manufacturing and Nano Integration Node. Computing resources on the Lipscomb High Performance Computing Cluster were provided by the University of Kentucky Information Technology Department and the Center for Computational Sciences (CCS).

Funders	Funder number
Oak Ridge National Laboratory
National Science Foundation Office of International Science and Engineering
NLK
College of Arts and Sciences, University of North Dakota
U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center	DMR-2104296, 24432, DE-SC0022315
U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center
American Chemical Society Petroleum Research Fund	67748-ND10
American Chemical Society Petroleum Research Fund
University of Kentucky	DMR-2104296
University of Kentucky
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China	OIA 2327349, CBET 2018411
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1039/d5ra00712g

Cite this

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title = "Green synthesis of ultrathin WS2 nanosheets for efficient hydrogen evolution reaction",

abstract = "Transition metal dichalcogenide (TMD) nanostructures have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) as there is an increasing demand for cost-effective and sustainable hydrogen production. Despite significant progress, there is still a critical need for developing facile and green methods for synthesizing ultrathin TMD nanostructures. In this study, we introduce a green, top-down synthesis method to produce highly exfoliated WS2 nanosheets. The process combines the ultrasonication of bulk WS2 in a binary water-ethanol solvent with a solvothermal treatment. The resulting ultrathin WS2 nanosheets exhibit clean surfaces free of surface ligands and impurities, high crystallinity in the semiconducting hexagonal phase, and outstanding electrochemical activity for HER. Key performance metrics include a low onset potential of −0.32 V (vs. reversible hydrogen electrode (RHE)) at 10 mA cm−2 and a low Tafel slope of 160 mV dec−1 with a catalyst loading of 0.76 mg cm−2. The promising HER performance is attributed to (1) a high density of exposed edges and defects, (2) enhanced charge transport due to high crystallinity, and (3) clean surfaces enabling efficient interfacial electron transfer. Furthermore, operando Raman spectroscopy using a 3D-printed electrochemical cell identifies the catalytically active sites on WS2 nanosheets for HER. This work provides a green route to high-performance, low-dimensional electrocatalysts for sustainable hydrogen production.",

author = "Kothalawala, \{Nadeesha L.\} and Nipun Chandrasiri and \{De Alwis Goonatilleke\}, Manisha and Rao, \{Keerthan R.\} and Sujan Shrestha and Kodithuwakku, \{Udari S.\} and Kim, \{Irene Y.\} and Chad Risko and Ambrose Seo and Guiton, \{Beth S.\} and Fuqian Yang and Kim, \{Doo Young\}",

note = "Publisher Copyright: {\textcopyright} 2025 The Royal Society of Chemistry.",

year = "2025",

month = jun,

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doi = "10.1039/d5ra00712g",

language = "English",

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AU - Kothalawala, Nadeesha L.

AU - Chandrasiri, Nipun

AU - De Alwis Goonatilleke, Manisha

AU - Rao, Keerthan R.

AU - Shrestha, Sujan

AU - Kodithuwakku, Udari S.

AU - Kim, Irene Y.

AU - Risko, Chad

AU - Seo, Ambrose

AU - Guiton, Beth S.

AU - Yang, Fuqian

AU - Kim, Doo Young

PY - 2025/6/9

Y1 - 2025/6/9

N2 - Transition metal dichalcogenide (TMD) nanostructures have emerged as promising electrocatalysts for the hydrogen evolution reaction (HER) as there is an increasing demand for cost-effective and sustainable hydrogen production. Despite significant progress, there is still a critical need for developing facile and green methods for synthesizing ultrathin TMD nanostructures. In this study, we introduce a green, top-down synthesis method to produce highly exfoliated WS2 nanosheets. The process combines the ultrasonication of bulk WS2 in a binary water-ethanol solvent with a solvothermal treatment. The resulting ultrathin WS2 nanosheets exhibit clean surfaces free of surface ligands and impurities, high crystallinity in the semiconducting hexagonal phase, and outstanding electrochemical activity for HER. Key performance metrics include a low onset potential of −0.32 V (vs. reversible hydrogen electrode (RHE)) at 10 mA cm−2 and a low Tafel slope of 160 mV dec−1 with a catalyst loading of 0.76 mg cm−2. The promising HER performance is attributed to (1) a high density of exposed edges and defects, (2) enhanced charge transport due to high crystallinity, and (3) clean surfaces enabling efficient interfacial electron transfer. Furthermore, operando Raman spectroscopy using a 3D-printed electrochemical cell identifies the catalytically active sites on WS2 nanosheets for HER. This work provides a green route to high-performance, low-dimensional electrocatalysts for sustainable hydrogen production.

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