Self-Adaptive Nonstoichiometric High-Entropy Intermetallics Enable Durable Oxygen Evolution under Industrial Current...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Scalable hydrogen production via water electrolysis is vital for clean energy.
• Oxygen evolution reaction (OER) catalysts face an activity-stability trade-off, hindering industrial application.
• Existing catalysts often lack the required durability under high current densities.

Purpose of the Study:

• To develop a catalyst that simultaneously achieves high activity and durability for the oxygen evolution reaction.
• To overcome the inherent limitations of current OER catalysts.
• To demonstrate the potential of nonstoichiometric high-entropy intermetallics for industrial electrocatalysis.

Main Methods:

• Synthesis of a nonstoichiometric high-entropy intermetallic (HEI) catalyst with a B2 NiAl-type structure.
• Hierarchical porous architecture design for enhanced surface area.
• Electrochemical testing under industrial current densities (up to 1 A cm⁻²).
• Atomic-resolution characterization and theoretical calculations.
• Integration into a 3D-printed catalytic plate for anion-exchange membrane electrolyzers.

Main Results:

• The HEI catalyst achieved an ultralow overpotential of 359 mV at 1 A cm⁻².
• Demonstrated stable operation for over 2000 hours under fluctuating current densities (0.5–2 A cm⁻²).
• Outperformed noble metal benchmarks (RuO₂/IrO₂) and state-of-the-art catalysts.
• 3D-printed catalytic plate delivered 1 A cm⁻² at 1.72 V in an electrolyzer with sustained stability.
• Mechanism revealed adaptive Al-sacrificing and reduced lattice oxygen involvement.

Conclusions:

• Nonstoichiometric high-entropy intermetallics intrinsically overcome the activity-stability trade-off in OER catalysis.
• The developed HEI catalyst shows exceptional performance and durability, suitable for industrial hydrogen production.
• This work establishes a design principle for robust and scalable electrocatalysts using self-adaptive intermetallics.