Stable High-Entropy Alloy AlCoCrFeNi_2.1 with Anti-Dealloying Effect for Enhanced Oxygen Evolution Performance

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Catalyst stability is crucial for efficient water electrolysis.
• Aluminum (Al) offers active sites but suffers from instability in catalytic environments.
• High-entropy alloys (HEAs) present tunable properties for catalytic applications.

Purpose of the Study:

• To synthesize and characterize Al-containing single-phase HEAs for oxygen evolution reaction (OER) catalysis.
• To investigate the effect of aluminum content on HEA structure, particle size, and catalytic performance.
• To enhance the stability and efficiency of OER catalysts for water electrolysis.

Main Methods:

• Gas atomization method (GAM) for synthesizing AlCoCrFeNi$_{2.1}$ HEAs with varying Al content (x = 0–1).
• Characterization of alloy structure (BCC phase) and particle size.
• Electrochemical testing for OER performance evaluation.
• COMSOL simulations and Density Functional Theory (DFT) calculations for mechanistic insights.

Main Results:

• GAM produced single-phase BCC structured HEAs, preventing phase separation.
• Increasing Al content in AlCoCrFeNi$_{2.1}$ alloys controlled particle size and improved OER performance.
• AlCoCrFeNi$_{2.1}$ exhibited excellent OER performance with a low overpotential (≈313 mV at 100 mA·cm^-2 over 1000 h).

Conclusions:

• Al-containing HEAs, particularly AlCoCrFeNi$_{2.1}$, offer a promising strategy to enhance OER catalyst stability and performance.
• This work provides a controllable method for developing element-dependent catalysts for water electrolysis.
• The findings contribute to advancing efficient and durable electrocatalysts for energy applications.