Sequential-chain coupling over hierarchical click-sites enables highly selective urea electrosynthesis

Area of Science:

• Electrochemistry
• Catalysis
• Sustainable Chemistry

Background:

• Electrochemical C-N coupling for urea synthesis faces challenges due to complex mechanisms and intermediate mismatch.
• Developing efficient and selective catalysts is crucial for sustainable nitrogen and carbon fixation.

Purpose of the Study:

• To design a catalyst enabling a sequential-chain coupling pathway for efficient urea electrosynthesis.
• To overcome the spatiotemporal mismatch between carbon and nitrogen intermediates in urea formation.

Main Methods:

• Design and synthesis of a hierarchical click-site catalyst (Se-InOx) inspired by click chemistry.
• Electrochemical experiments to study urea electrosynthesis pathway and intermediate formation.
• Mechanistic studies including in-situ adsorption and hydrogenation analysis.
• Techno-economic analysis and scalable synthesis validation.

Main Results:

• Achieved a urea yield rate of 254.94 mmol h⁻¹ g⁻¹, 78.61% Faradaic efficiency, and >85% Nurea-selectivity.
• Demonstrated 100% Curea-selectivity by controlling intermediate adsorption and reaction sequence.
• Identified Se-InOx as a dual click-site catalyst facilitating selective NO3- hydrogenation to *NO2, followed by CO2 coupling.

Conclusions:

• The sequential-chain coupling strategy effectively resolves intermediate mismatch, enhancing C-N coupling selectivity for urea electrosynthesis.
• The developed Se-InOx catalyst provides a feasible blueprint for high-selectivity multicomponent electrosynthesis.
• This approach offers a sustainable route for urea production with potential for industrial scalability.