Wrinkled Strain-Enriched High-Entropy Metallene Enables Cross-Site Tandem Nitrate-to-Ammonia

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-entropy alloys (HEAs) show promise for electrocatalytic nitrate-to-ammonia (NRA) conversion.
• Existing HEAs face challenges like low atom utilization and limited active site exposure.

Purpose of the Study:

• To develop a high-entropy metallene (HEM) catalyst for enhanced NRA conversion.
• To address limitations in atom utilization and active site exposure in HEA catalysts.

Main Methods:

• Synthesized a wrinkled PdFeCoNiCuIn high-entropy metallene (HEM).
• Employed a structural-electronic dual regulation strategy involving indium (In) incorporation.
• Investigated p-d orbital hybridization and metallene architecture effects.
• Analyzed the cross-site tandem catalytic pathway decoupling nitrate activation and ammonia desorption.

Main Results:

• The PdFeCoNiCuIn-HEM achieved 99.3% ammonia Faradaic efficiency and a yield rate of 4.55 mmol h⁻¹ mg⁻¹.
• The catalyst demonstrated a broad adsorption energy landscape due to In-induced p-d hybridization.
• A rechargeable Zn-NO₃⁻ battery using the HEM cathode exhibited a 1.48 V open-circuit voltage and 7.36 mW cm⁻² power density.
• The battery showed stable cycling for over 100 hours.

Conclusions:

• The HEM catalyst effectively overcomes scaling constraints in NRA catalysis.
• The developed structural-electronic dual regulation strategy is practical and generalizable.
• This work offers a new design paradigm for efficient nitrate reduction reaction (NRA) catalysts.