Electrocatalytic Urea Synthesis via N₂ Dimerization and Universal Descriptor.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrocatalytic urea synthesis offers a sustainable alternative to industrial methods.
• Current methods face challenges in nitrogen fixation, C-N coupling, and catalyst design.
• A theoretical framework for efficient urea synthesis is lacking.

Purpose of the Study:

• To propose a novel mechanism for electrocatalytic urea synthesis via N₂ and CO coreduction.
• To identify highly active catalysts for this process.
• To develop a descriptor for guiding catalyst design.

Main Methods:

• Computational mechanism proposal.
• Density Functional Theory (DFT) calculations.
• Identification of transition metal catalysts (Ti2@C4N3, V2@C4N3).
• Development of a structure-activity relationship descriptor (effective d electron number, Φ).

Main Results:

• A new mechanism involving dimerized N₂ and CO insertion was proposed, bypassing N≡N bond cleavage.
• Ti₂@C₄N₃ and V₂@C₄N₃ catalysts showed high activity with low onset potentials (-0.741 and -0.738 V).
• The effective d electron number (Φ) descriptor was introduced to correlate catalyst structure with urea formation activity.

Conclusions:

• The proposed mechanism provides a feasible pathway for electrocatalytic urea synthesis.
• The identified catalysts demonstrate significant potential for efficient urea production.
• The Φ descriptor offers a universal guiding principle for designing novel urea electrocatalysts.