Battery-Driven N₂ Electrolysis Enabled by High-Entropy Catalysts: From Theoretical Prediction to Prototype Model

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Decentralized ammonia (NH₃) production via nitrogen (N₂) splitting offers an alternative to the Haber-Bosch process.
• Sluggish kinetics in N₂ reduction reaction (NRR) and oxygen evolution reaction (OER) impede device design.

Purpose of the Study:

• To predict and develop high-entropy oxides (HEOs) as efficient catalysts for NRR and OER.
• To construct and evaluate a standalone N₂ electrolysis device utilizing HEOs.

Main Methods:

• Density functional theory (DFT) predictions for HEOs.
• Facile synthesis of sea urchin-shaped HEOs from ultrathin nanosheets.
• Electrocatalytic activity testing for NRR and OER.
• Construction and testing of a prototype N₂ electrolysis device.

Main Results:

• HEOs exhibit excellent electrocatalytic activity for NRR (47.58 µg h^-1 mg^-1, 10.74% FE) and OER (215 mV @10 mA cm^-2).
• The prototype device achieves a notable NH₃ yield rate of 41.11 µg h^-1 mg^-1 with 14.14% FE.
• Mechanism studies reveal synergistic multi-metal and entropy effects contribute to catalytic performance.

Conclusions:

• HEOs are effective catalysts for promoting both NRR and OER, enabling efficient decentralized ammonia synthesis.
• The developed HEO-based device offers a promising pathway for scalable ammonia production.
• This work provides insights into designing versatile catalysts and devices for industrial applications.