Surface Reconstruction Enabled Efficient Hydrogen Generation on a Cobalt-Iron Phosphate Electrocatalyst in Neutral...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Direct seawater splitting for hydrogen production is hindered by slow water dissociation kinetics in neutral media.
• Efficient hydrogen evolution reaction (HER) in neutral conditions is crucial for practical seawater electrolysis.

Purpose of the Study:

• To develop a novel electrocatalyst for efficient HER in neutral conditions and direct seawater splitting.
• To improve the sluggish water dissociation kinetics in neutral electrolytes using a simple electrode design strategy.

Main Methods:

• Fabrication of a free-standing bimetallic cobalt-iron phosphate electrode.
• In situ electrochemical reduction to reconstruct the electrode surface into an (oxy)hydroxide layer.
• Electrocatalytic performance testing in buffered electrolyte and natural seawater.

Main Results:

• The reconstructed electrode exhibited significantly improved HER activity in both buffered and natural seawater.
• The electrocatalyst required low overpotentials (97 mV for 10 mA cm⁻², 198 mV for 100 mA cm⁻²) in a neutral buffer, outperforming platinum.
• Mechanistic studies confirmed the role of oxophilic (oxy)hydroxide species in enhancing HER activity.

Conclusions:

• In situ reconstruction of bimetallic cobalt-iron phosphate is an effective strategy for creating active HER electrocatalysts.
• The developed electrocatalyst demonstrates high efficiency for direct seawater splitting, overcoming kinetic limitations.
• This approach offers significant potential for advancing electrocatalysts for sustainable hydrogen production.