Pore Engineering for Directional CO₂ Enrichment in Urea Electrosynthesis

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Science

Background:

• Electrochemical urea synthesis from CO2 and nitrate presents a sustainable route for carbon emission and nitrogen pollution mitigation.
• Challenges include low C-N coupling selectivity, competing hydrogen evolution, and poor CO2 utilization.

Purpose of the Study:

• To develop a nanopore-structure engineering strategy for metal-free porous carbon frameworks to enhance urea synthesis.
• To improve CO2 binding affinity and utilization while suppressing hydrogen evolution.

Main Methods:

• Implemented nanopore-structure engineering in metal-free porous carbon frameworks.
• Tailored pore length and surface chemistry, including oxygen functionalization.
• Investigated gas-liquid-solid interactions and capillary gating effects.

Main Results:

• Oxygen-functionalized surfaces enhanced CO2 binding via dipole-quadrupole interactions.
• Elongated pores created a H2O-deficient nanoenvironment, prolonging CO2 residence time.
• Achieved a 28% increase in Faradaic efficiency and 12% improvement in urea yield.

Conclusions:

• Nanopore-level design is a novel concept for optimizing porous carbon supports in electrocatalysis.
• This strategy effectively enhances urea selectivity and suppresses hydrogen evolution.
• The approach offers a pathway for rational development of catalysts for sustainable chemical synthesis.