Self-Supported Nanoporous High-Entropy Alloy Electrodes with W-Modulated Surface Reconstruction for Alkaline Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and durable non-noble catalysts are essential for alkaline hydrogen evolution (HER).
• High-entropy alloys (HEAs) present a promising platform for HER catalysts due to their unique properties.
• Tuning HEA composition and structure is key to optimizing their catalytic performance.

Purpose of the Study:

• To investigate the effect of tungsten (W) on the structure and HER performance of nanoporous high-entropy alloys.
• To develop self-supported, dealloyed HEA electrodes for efficient alkaline HER.
• To understand the role of W in dealloying-induced reconstruction for enhanced catalysis.

Main Methods:

• Fabrication of HEA electrodes (Fe35Co25Ni30Mo10 and Fe35Co25Ni30Mo7W3) via arc melting.
• Electrochemical dealloying in 1 M HCl to create nanoporous structures.
• Characterization using X-ray diffraction (XRD) and scanning electron microscopy (SEM).
• Electrochemical evaluation of HER activity in 1 M KOH.

Main Results:

• Both dealloyed HEAs retained an FCC framework, with W promoting a more continuous nanoporous structure.
• Dealloyed Fe35Co25Ni30Mo7W3 exhibited superior HER activity, requiring a lower overpotential (178 mV at 10 mA cm-2).
• The W-containing HEA demonstrated faster kinetics (Tafel slope 98.5 mV dec-1) and higher electrochemical double-layer capacitance (19.2 mF cm-2).

Conclusions:

• Tungsten incorporation and dealloying-induced reconstruction are effective strategies for creating robust nanoporous HEA electrodes.
• The developed HEA electrodes show significant potential as efficient non-noble catalysts for alkaline HER.
• This study provides insights into designing advanced materials for electrochemical energy conversion applications.