Two-Dimensional MoS₂ Confined Co(OH)₂ Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Developing cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable energy technologies.
• Achieving efficient HER in alkaline media faces challenges due to slow water dissociation and catalyst instability.

Purpose of the Study:

• To design and synthesize a novel 2D MoS2 confined Co(OH)2 nanoparticle electrocatalyst.
• To enhance HER activity and long-term stability in alkaline solutions.

Main Methods:

• A two-step synthesis involving lithium intercalation of MoS2 nanosheets followed by Co2+ exchange.
• Characterization using spectroscopic studies.
• Electrochemical testing and density functional theory (DFT) calculations.

Main Results:

• The synthesized Co-Ex-MoS2 catalyst exhibited superior HER activity with low onset overpotential (15 mV) and Tafel slope (53 mV dec-1).
• The catalyst demonstrated excellent durability in alkaline media.
• DFT calculations confirmed the synergistic effect of Co(OH)2 nanoparticles and MoS2 nanosheets for enhanced activity and stability.

Conclusions:

• The confined Co(OH)2 nanoparticles within MoS2 nanosheets provide an effective strategy for designing highly active and stable HER electrocatalysts in alkaline solutions.
• This approach offers a pathway for developing advanced, low-cost alternatives to platinum-based catalysts for HER.