Enabling Unconventional "Alternating-Distal" N₂ Reduction Pathway for Efficient Ammonia Electrosynthesis.

Area of Science:

• Electrocatalysis
• Materials Science
• Chemical Engineering

Background:

• Electrocatalytic nitrogen (N₂) reduction to ammonia (NH₃) is crucial for sustainable agriculture and industry.
• Conventional pathways (associative and distal) face challenges in N₂ activation and NH₃ selectivity.
• Developing efficient electrocatalysts and understanding reaction mechanisms are key research areas.

Purpose of the Study:

• To investigate an unconventional electrocatalytic pathway for N₂ reduction.
• To enhance ammonia (NH₃) synthesis efficiency and selectivity.
• To explore the role of amorphous CeMnOₓ electrocatalysts in N₂ reduction.

Main Methods:

• Utilized an amorphous cerium manganese oxide (CeMnOₓ) electrocatalyst.
• Investigated an unconventional "alternating-distal" reaction pathway.
• Employed in situ spectroscopic analyses and theoretical calculations to confirm the mechanism.

Main Results:

• Achieved N₂ activation via π back donation on the Mn site.
• Demonstrated Mn/Ce dual active sites regulating intermediates to prevent by-product formation.
• Attained a high ammonia production rate (82.8 µg h⁻¹ mg⁻¹) and Faradaic efficiency (37.3%) in neutral media.

Conclusions:

• Validated a novel "alternating-distal" mechanism for electrocatalytic ammonia synthesis.
• The CeMnOₓ electrocatalyst facilitates efficient N₂ activation and selective NH₃ production.
• This mechanistic insight can be applied to optimize other catalytic processes.