Engineering Atomic Copper-Based Solid Frustrated Lewis-Pair Sites toward Dilute CO2 Activation and Transformation

Solid frustrated Lewis pairs (FLPs) exhibit structural and electronic diversity for efficiently activating inert chemical bonds, yet their catalytic performances remain limited by irreversible aggregation of randomly distributed acid-base sites. Herein, we constructed an organic-inorganic cooperative FLP catalyst (C···CuSA FLP) within ordered confined space through anchoring Cu single atoms at N-heterocyclic olefin (NHO) sites in a robust metal-organic framework. The C···CuSA FLP catalyzes the carboxylative cyclization of propargylamines with CO2 to yield 2-oxazolidinones, achieving a record turnover frequency of 1548 h-1 among non-noble catalysts, and retaining impressive activities of 816 h-1 (simulated flue gas, 15 vol % CO2), 291 h-1 (simulated breath-level gas, 5 vol % CO2), and 5.0 h-1 (indoor air, ∼450 ppm of CO2). Combined operando spectroscopic experiments and density functional theory calculations elucidate that the electron-rich in situ generated NHO as a Lewis base activates CO2 to form a reversible NHO-CO2 adduct, enabling the subsequent kinetically favorable electrophilic addition. Meanwhile, the electron-deficient CuSA serves as a Lewis acid to activate the C≡C bond for promoting the nucleophilic attack step as well as triggering the intramolecular cyclization. These findings establish atomically precise solid FLP architectures as a transformative paradigm for highly efficient activation and conversion of CO2 from ambient air.