Dual CoS-Modified Tungsten Disulfide Double-Heterojunction Electrocatalyst for Efficient Hydrogen Evolution in All-pH...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient heterogeneous electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable energy technologies.
• Tungsten disulfide (WS₂)-based hybrid composites with pH-universal applicability for HER are scarce.
• Heterojunction engineering is a key strategy to enhance catalyst performance.

Purpose of the Study:

• To design and synthesize a novel WS₂-based hybrid catalyst with dual heterojunctions for pH-universal HER.
• To investigate the synergistic effects of double heterojunctions (WS₂/Co₄S₃ and WS₂/Co₉S₈) on HER activity.
• To explore the HER mechanism and potential applications in sustainable energy.

Main Methods:

• Fabrication of a WS₂/Co₉S₈/Co₄S₃ hybrid catalyst supported on a porous Co, N-codoped carbon (Co/NC) skeleton.
• Electrochemical characterization of the catalyst's HER performance in electrolytes across a wide pH range.
• Theoretical calculations (e.g., Gibbs free energy of H adsorption) to elucidate the catalytic mechanism.

Main Results:

• The novel WS₂/Co₉S₈/Co₄S₃ catalyst exhibits excellent HER activity and stability in all-pH media.
• Theoretical calculations confirm near-ideal Gibbs free energy for H* adsorption (close to 0.0 eV) at both WS₂/Co₉S₈ and WS₂/Co₄S₃ heterojunctions.
• The synergistic interaction between the dual heterojunctions significantly enhances catalytic performance compared to single heterojunctions or bare Co₉S₈/Co₄S₃.

Conclusions:

• The developed WS₂/Co₉S₈/Co₄S₃ hybrid catalyst demonstrates superior, pH-universal HER activity due to synergistic dual heterojunctions.
• The catalyst effectively decomposes H₂O and shows excellent performance in alkaline and neutral conditions.
• This work offers valuable insights into WS₂-based materials for advanced electrocatalysis and sustainable energy solutions.