Atom-level interaction design between amines and support for achieving efficient and stable CO capture.

Amine-functionalized adsorbents offer substantial potential for CO capture owing to their selectivity and diverse application scenarios. However, their effectiveness is hindered by low efficiency and unstable cyclic performance. Here we introduce an amine-support system designed to achieve efficient and stable CO capture. Through atom-level design, each polyethyleneimine (PEI) molecule is precisely impregnated into the cage-like pore of MIL-101(Cr), forming stable composites via strong coordination with unsaturated Cr acid sites within the crystal lattice. The resulting adsorbent demonstrates a low regeneration energy (39.6 kJ/mol), excellent cyclic stability (0.18% decay per cycle under dry CO regeneration), high CO adsorption capacity (4.0 mmol/g), and rapid adsorption kinetics (15 min for saturation at 30 °C). These properties stem from the unique electron-level interaction between the amine and the support, effectively preventing carbamate products' dehydration. This work presents a feasible and promising cost-effective and sustainable CO capture strategy.