Multi-Anion Electrocatalysts Stabilized by Anionic Configurational Entropy for Advanced Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Anion regulation in transition metal compounds is key for electrocatalyst tuning.
• Multiple anions often lead to phase separation, limiting active site density and tunability.

Purpose of the Study:

• To extend the high-entropy strategy to anion regulation for stable single-phase multi-anion compounds.
• To achieve atomic-level anion homogeneity for precise electronic structure modulation.

Main Methods:

• Synthesized a multi-anion electrocatalyst with hydroxide, sulfide, selenide, and phosphate anions.
• Evaluated electrocatalytic activity for hydrogen and oxygen evolution reactions.
• Tested the catalyst in an anion-exchange membrane water electrolyzer.

Main Results:

• Achieved low overpotentials: 25 mV for hydrogen evolution and 146 mV for oxygen evolution (at 10 mA cm⁻²).
• Demonstrated high performance in water electrolysis: 1,000 mA cm⁻² at 1.98 V.
• Maintained stable operation for 200 hours at 25 °C.

Conclusions:

• Anionic configurational entropy stabilizes multi-anion compounds, overcoming phase separation.
• This work broadens the scope of high-entropy materials for electrocatalysis.
• Provides a design strategy for next-generation electrocatalysts.