Structural and Electronic Optimization of MoS₂ Edges for Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Molybdenum disulfide (MoS2) edge sites are crucial for efficient hydrogen evolution reaction (HER).
• Activating and increasing the accessibility of these MoS2 edge sites is key to improving HER performance.
• Existing MoS2-based catalysts often face limitations in activity and accessibility.

Purpose of the Study:

• To fabricate a novel electrocatalyst combining ultrasmall, nitrogen-doped MoS2 nanocrystals (N-MoS2) with a porous carbon network (CN).
• To investigate the synergistic effects of nitrogen doping and porous carbon confinement on MoS2 edge site activity and accessibility for HER.
• To evaluate the catalytic performance and stability of the developed N-MoS2/CN material for HER.

Main Methods:

• A self-templating strategy was employed to synthesize N-MoS2 nanocrystals confined within a porous carbon network.
• Experimental characterization techniques were used to analyze the material's structure and properties.
• Density functional theory (DFT) calculations were performed to understand the electronic structure and catalytic mechanisms.

Main Results:

• The fabricated N-MoS2/CN material exhibited enhanced MoS2 edge site activation due to nitrogen doping.
• The porous carbon network provided high accessibility to the active N-MoS2 sites.
• The N-MoS2/CN demonstrated superior HER activity with a low overpotential (114 mV at 10 mA cm-2) and excellent long-term stability (>10 h).

Conclusions:

• The N-MoS2/CN electrocatalyst represents one of the best MoS2-based materials for HER to date.
• Synergistic structural and electronic modulations of MoS2 edges by N-doping and porous carbon confinement are effective for boosting HER efficiency.
• This work offers a new strategy for designing advanced electrocatalysts with enhanced accessible active sites for energy conversion applications.