Fe-Rich Medium-Entropy Core-Shell Electrocatalyst for Hydrogen Evolution Reaction Under Large Current Density

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Platinum (Pt) based catalysts are expensive and suffer from low stability under high current densities, hindering efficient green hydrogen production.
• Development of stable, efficient, and cost-competitive electrocatalysts is crucial for advancing hydrogen evolution reaction (HER) technologies.

Purpose of the Study:

• To synthesize and evaluate a novel Fe-rich medium-entropy alloy (MEA) catalyst with a core-shell structure for enhanced hydrogen evolution reaction (HER) performance.
• To investigate the catalytic activity, durability, and underlying mechanisms of the MEA catalyst in alkaline media.

Main Methods:

• Synthesis of a core-shell structured Fe-rich medium-entropy alloy (MEA) catalyst featuring a near-zero-resistance homogeneous interface.
• Electrochemical characterization of the MEA catalyst, including overpotential measurements at 1,000 mA cm⁻² and Tafel slope analysis in 1.0 M KOH.
• Comparison of the MEA catalyst's performance against the benchmark 20% Pt/C catalyst.

Main Results:

• The synthesized low-cost MEA catalyst exhibited outstanding durability and catalytic activity, with an overpotential of 343.6 mV at 1,000 mA cm⁻² and a Tafel slope of 67.6 mV dec⁻¹.
• These results significantly outperformed the benchmark 20% Pt/C catalyst (416.9 mV, 156.8 mV dec⁻¹).
• The enhanced performance is attributed to the highly conductive homogeneous interface facilitating electron injection from the metallic core to the medium entropy oxide (MEO) shell, activating Fe/Ni/Co sites for efficient hydrogen evolution.

Conclusions:

• The novel Fe-rich MEA catalyst demonstrates significant potential as a stable and efficient electrocatalyst for industrial high-current hydrogen evolution applications.
• The core-shell structure with a homogeneous interface strategy offers a promising pathway for developing advanced, cost-competitive catalysts for green hydrogen production.
• This work broadens the application prospects of medium-entropy alloys (MEAs) in electrochemical energy conversion.