Pore Engineering for Directional CO2 Enrichment in Urea Electrosynthesis

Electrochemical synthesis of urea from CO2 and nitrate offers a sustainable pathway to address both carbon emissions and nitrogen pollution. However, achieving high C–N coupling selectivity remains challenging due to competing hydrogen evolution reactions and insufficient CO2 utilization. Herein, we implement a nanopore-structure engineering strategy to precisely tailor pore length and surface chemistry in metal-free porous carbon frameworks. Oxygen-functionalized surfaces augment CO2 binding affinity via dipole–quadrupole interactions, while elongated pores induce directional CO2 enrichment by establishing a H2O-deficient nanoenvironment that prolongs the residence time of CO2 through capillary gating. This dual modulation of gas–liquid–solid interactions enhances urea selectivity and suppresses hydrogen evolution, yielding a 28% increase in Faradaic efficiency and 12% improvement in urea yield. Our findings propose a novel nanopore-level design concept that shall support the rational development of porous carbon supports across gas–liquid–solid electrocatalytic systems.