Robust Alkaline Hydrogen Evolution From Ru-degenerate Doped WS₂/WSe₂ p-n Junction Heterostructure Electrocatalyst.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Heterostructure engineering is a key strategy for developing efficient electrocatalysts for water splitting.
• Van der Waals heterostructures offer unique properties for charge transfer but often show limited hydrogen evolution reaction (HER) performance in alkaline media compared to platinum.
• Developing cost-effective and highly active catalysts for electrochemical energy generation remains a significant challenge.

Purpose of the Study:

• To design and synthesize a novel Ruthenium-degenerate doped WS2/WSe2 (Ru-WS2/WSe2) p-n junction heterostructure catalyst.
• To evaluate the HER activity and stability of the Ru-WS2/WSe2 catalyst in an alkaline medium.
• To investigate the potential of 2D material-based heterostructures for efficient electrochemical energy generation.

Main Methods:

• Synthesis of WS2/WSe2 and Ru-WS2/WSe2 heterostructures.
• Characterization of heterostructures to confirm p-n junction formation via rectification behavior.
• Electrochemical testing of the catalyst for hydrogen evolution reaction (HER) in 1 M KOH, including overpotential and Tafel slope measurements.
• Evaluation in a symmetric full cell water electrolyzer.

Main Results:

• The WS2/WSe2 and Ru-WS2/WSe2 heterostructures exhibited diode rectification behavior, confirming p-n junction formation.
• The Ru-WS2/WSe2 catalyst achieved a current density of 10 mA cm⁻² at an overpotential of 47 mV vs. RHE with a low Tafel slope of 25 mV dec⁻¹.
• The catalyst demonstrated superior HER performance compared to commercial Pt/C in 1 M KOH and required 1.43 V for 10 mA cm⁻² in a full water electrolyzer.

Conclusions:

• The Ru-degenerate doped WS2/WSe2 p-n junction heterostructure is a highly efficient and stable electrocatalyst for HER in alkaline media.
• This study highlights the potential of 2D material-based heterostructures for low-cost and high-performance electrochemical energy applications.
• The findings pave the way for designing advanced catalysts for water splitting and other energy conversion technologies.