Simultaneous Capture of CO2 Boosting Its Electroreduction in the Micropores of a Metal-organic Framework

Abstract

Integration of CO₂ capture capability from simulated flue gas and electrochemical CO₂ reduction reaction (eCO₂ RR) active sites into a catalyst is a promising cost-effective strategy for carbon neutrality, but is of great difficulty. Herein, combining the mixed gas breakthrough experiments and eCO₂ RR tests, we showed that an Ag₁₂ cluster-based metal-organic framework (1-NH₂ , aka Ag₁₂ bpy-NH₂ ), simultaneously possessing CO₂ capture sites as "CO₂ relays" and eCO₂ RR active sites, can not only utilize its micropores to efficiently capture CO₂ from simulated flue gas (CO₂ : N₂ =15 : 85, at 298 K), but also catalyze eCO₂ RR of the adsorbed CO₂ into CO with an ultra-high CO₂ conversion of 60 %. More importantly, its eCO₂ RR performance (a Faradaic efficiency (CO) of 96 % with a commercial current density of 120 mA cm^-2 at a very low cell voltage of -2.3 V for 300 hours and the full-cell energy conversion efficiency of 56 %) under simulated flue gas atmosphere is close to that under 100 % CO₂ atmosphere, and higher than those of all reported catalysts at higher potentials under 100 % CO₂ atmosphere. This work bridges the gap between CO₂ enrichment/capture and eCO₂ RR.

Keywords: CO2 Enrichment/Capture; CO2 Relays; Electrochemical CO2 Reduction; Metal-Organic Framework; Simulated Flue Gas.