Continuous ammonia electrosynthesis using physically interlocked bipolar membrane at 1000 mA cm^-2.

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Ammonia electrosynthesis from nitrate offers mild conditions and clean energy benefits.
• Existing methods suffer from low yield and short duration due to unstable ion exchange membranes at high current densities.

Purpose of the Study:

• To develop a stable and efficient bipolar membrane reactor for continuous ammonia electrosynthesis from nitrate.
• To overcome limitations of existing electrochemical strategies by enhancing ionic transfer and interfacial stability.

Main Methods:

• A bipolar membrane with a 3D physically interlocked interface was constructed to improve water dissociation and ionic transfer.
• A Co 3D nanoarray cathode was integrated for high current and low concentration utilization.
• The system was tested for continuous electrolysis under demanding conditions.

Main Results:

• The bipolar membrane design reduced transmembrane voltage to 1.13 V at 1000 mA cm⁻².
• The reactor achieved stable electrolysis at 1000 mA cm⁻² for over 100 hours.
• High Faradaic efficiency (86.2%) and yield rate (68.4 mg h⁻¹ cm⁻²) were obtained with a 2000 ppm nitrate electrolyte.

Conclusions:

• The proposed bipolar membrane nitrate reduction process significantly enhances ionic transfer and interfacial stability.
• This advanced reactor design demonstrates a promising pathway for continuous, high-yield ammonia electrosynthesis.
• The findings hold potential for advancing artificial nitrogen cycling applications.