High-Entropy Alloy Heterostructures with Tailored Interfacial Microenvironments for Efficient Electrocatalytic Water...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-entropy alloys (HEAs) provide a unique platform for designing advanced electrocatalysts.
• Heterogeneous interfaces in HEAs enhance catalytic activity and durability through synergistic multi-metal interactions.

Purpose of the Study:

• To develop a heterostructured bifunctional electrocatalyst for efficient hydrogen and oxygen evolution reactions (HER and OER).
• To investigate the role of interfacial engineering in HEAs for electrocatalysis.

Main Methods:

• Synthesis of a CrFeCoNiRu-RuNi (HEA-RuNi) heterostructured catalyst.
• Electrochemical measurements (HER, OER) in alkaline media.
• In situ Raman spectroscopy and electrochemical impedance spectroscopy (EIS).
• Theoretical calculations (DFT).

Main Results:

• HEA-RuNi exhibited low overpotentials: 48 mV for HER and 249 mV for OER at 10 mA cm⁻².
• The catalyst demonstrated robust stability for 200 hours in an anion exchange membrane water electrolysis device.
• In situ techniques and theoretical calculations revealed that the heterostructure modulates the Ru microenvironment and electronic structure, facilitating water dissociation and optimizing intermediate adsorption.

Conclusions:

• The heterostructured HEA-RuNi catalyst offers exceptional bifunctional electrocatalytic activity and stability.
• Interfacial engineering in HEAs is crucial for optimizing electrocatalyst performance by controlling the local electronic and chemical environment.
• This work provides insights into designing high-performance electrocatalysts for energy storage and conversion applications.