Sub-3 nm High-Entropy Alloy Nanoparticles with Triple Functionalities for Efficient Electrolytic Hydrogen Production

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-entropy alloys (HEAs) show potential for alkaline hydrogen evolution reaction (HER) due to tunable structures.
• Current HEA catalysts face challenges like low atomic utilization, insufficient current density, and unclear catalytic mechanisms.

Purpose of the Study:

• To develop a novel HEA catalyst for enhanced alkaline HER performance.
• To elucidate the catalytic mechanism of the HEA for hydrogen production.

Main Methods:

• Synthesis of ultrasmall sub-3 nm PtRuFeCoNiCu HEA nanoparticles on carbon fiber paper (CFP) using an ultraquick thermal shock strategy.
• Electrochemical characterization of the catalyst's performance in alkaline media.
• In situ Raman spectroscopy and density functional theory (DFT) calculations to validate the catalytic mechanism.

Main Results:

• The synthesized ultrasmall HEA nanoparticles (us-HEA/CFP) achieved state-of-the-art performance with ultralow overpotentials (31.4 mV at -100 mA cm⁻² and 102.5 mV at -1000 mA cm⁻²).
• Demonstrated a triple-functional catalytic surface involving Ru for water dissociation, FeCoNiCu for H* diffusion, and Pt for H* combination.
• An anion exchange membrane electrolyzer using the catalyst required only 1.94 V for 1000 mA cm⁻² and operated stably for 500 hours.

Conclusions:

• The developed us-HEA/CFP catalyst significantly enhances alkaline HER efficiency through a synergistic multi-site catalytic mechanism.
• The findings provide a new strategy for designing high-performance HEA electrocatalysts for efficient hydrogen production.
• The catalyst shows strong potential for practical, large-scale applications in alkaline water electrolysis.