A High-Entropy Oxide as High-Activity Electrocatalyst for Water Oxidation.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-entropy materials offer tunable properties for advanced catalysts.
• Oxygen evolution reaction (OER) is critical for electrochemical energy conversion.
• Earth-abundant catalysts are needed for energy-efficient technologies.

Purpose of the Study:

• Investigate the role of multication composition in high-entropy perovskite oxides (HEOs) for OER catalysis.
• Compare the OER activity of HEOs with parent single-site perovskites.
• Establish a composition-function relationship for HEO electrocatalysts.

Main Methods:

• Epitaxial growth of high-entropy perovskite oxide (LaCr0.2Mn0.2Fe0.2Co0.2Ni0.2O3-δ) and parent compounds.
• Electrocatalytic activity measurements for the oxygen evolution reaction (OER).
• X-ray photoemission spectroscopy (XPS) for surface and electronic structure analysis.

Main Results:

• The HEO demonstrated significantly higher OER activity (17-680x current) compared to single-site perovskites.
• Results indicate an intrinsic composition-function relationship due to epitaxial growth.
• XPS revealed synergistic effects between transition metal cations during OER.

Conclusions:

• High-entropy perovskite oxides are highly promising earth-abundant materials for high-activity OER electrocatalysts.
• HEOs enable tuning of catalytic activity beyond conventional limits.
• This work paves the way for efficient electrochemical energy storage and green hydrogen generation.