Engineering a Local Free Water Enriched Microenvironment for Surpassing Platinum Hydrogen Evolution Activity.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Optimizing the catalyst-electrolyte interface is crucial for efficient electrocatalysts.
• Pushing reactants into the inner Helmholtz plane (IHP) is challenging due to the elusive electrochemical IHP and inert catalyst surfaces.

Purpose of the Study:

• To engineer the electrochemical microenvironment using surface hydroxyl groups.
• To enhance alkaline hydrogen evolution activity by manipulating the catalyst-electrolyte interface.

Main Methods:

• Introduction of local force fields via surface hydroxyl groups.
• Utilizing a hydroxyl group immobilized Ni/Ni3C heterostructure as a prototype.
• Investigating the role of hydrogen bonding and polarization effects.

Main Results:

• Surface hydroxyl groups induce local hydrogen bonding, dragging water molecules across the IHP to the catalytic sites.
• The Ni/Ni3C heterostructure coupled with hydroxyl groups lowers water dissociation energy via polarization.
• Hydroxyl-rich catalysts demonstrate superior activity compared to Pt/C at high current densities (500 mA cm⁻² @ ≈276 mV) in alkaline media.

Conclusions:

• Surface hydroxyl groups effectively engineer the catalyst-electrolyte interface for enhanced electrocatalysis.
• This strategy provides a novel pathway for developing highly active alkaline hydrogen evolution electrocatalysts.
• The findings offer a new method for manipulating reactant supply at the electrochemical interface.