Mixed-Valence Intermetallic Compounds for Urea Electrosynthesis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Efficient urea electrosynthesis requires synchronized kinetics of CO2 and nitrate reduction.
• Atomic-scale active sites are crucial for C-N coupling and reaction control.
• Current catalysts face challenges in stability and synchronized kinetic regulation.

Purpose of the Study:

• To design and synthesize a catalyst with stable, distinct active sites for synchronized CO2 and nitrate reduction.
• To investigate the role of multivalent active sites in facilitating C-N coupling for urea synthesis.
• To establish a new paradigm for designing high-performance electrocatalysts for organic synthesis.

Main Methods:

• Synthesis of a mixed-valence intermetallic compound (Mv-IMC) Cu2Sb.
• Electrochemical characterization to study reaction kinetics and intermediate stabilization.
• Mechanistic studies to elucidate the role of Cu+/Cu2+ dual-sites.

Main Results:

• The Cu2Sb catalyst features Cu+/Cu2+ dual-sites that regulate and synchronize CO2 and nitrate reduction.
• These dual-sites stabilize key intermediates (*CO and *NO), lowering the C-N coupling energy barrier.
• Achieved a urea yield of 22.9 mmol h-1 gcat-1 with 64.9% Faradaic efficiency, stable over 200 h.

Conclusions:

• Mixed-valence intermetallic compounds (Mv-IMCs) offer a promising platform for designing electrocatalysts.
• Precise construction of multivalent active sites is key to enhancing urea electrosynthesis.
• This work provides a new strategy for developing efficient electrocatalysts for value-added organic synthesis.