Dual-confinement of reconstructed covalent organic framework for enhanced CO2 electrolysis in acid
Electrochemical CO2 reduction reaction (CO2RR) offers an attractive route to produce value-added multicarbon (C2+) products, yet suffers from competing hydrogen evolution and monocarbon production. Here, we propose a dual-confinement effect on CO2 reactant and *CO intermediate, induced by tuning the pore configuration of reconstructed covalent organic frameworks (RC-COFs). The highly crystalline microporous RC-COF-1, when coated on a Cu electrode, enhances local CO2 concentration and restricts CO diffusion, thereby promoting C-C coupling. In acidic electrolyte, the RC-COF-1@Cu electrode achieves a maximum C2+ Faradaic efficiency (FE) of 67.0% at 500 mA cm−2, while maintaining a total carbon product FE above 90% across a broad current density range (100–500 mA cm−2). Experimental and theoretical analyses confirm that the ordered micropores of RC-COF-1 modulate reactant adsorption and intermediate diffusion, leading to improved C2+ selectivity. This work underscores the critical role of COF pore architecture in microenvironment engineering for heterogeneous catalysis.