Basic Alkylamine Functionalized PAF‐1 Hybrid Membrane with High Compatibility for Superior CO₂ Separation from Flue Gas

Abstract Functionalized porous aromatic frameworks (PAFs) are excellent candidate materials for hybrid membrane fabrication. However, tailoring PAFs for membrane CO₂ separation with desirable performance is still a challenge. Here, facile fabrication of functional hybrid alkylamine‐modified PAF‐1 containing membranes with high compatibility for efficient CO₂/N₂ separation is reported. The methylamino groups are installed on PAF‐1 resulting in PAF‐1‐CH₂NH₂ that has a high surface area of over 1400 m² g^–1 and unique CO₂ adsorption with CO₂/N₂ thermodynamic selectivity of over 1000. Amidation reaction is developed for PAF‐1‐CH₂NH₂ cross linking with cPIM‐1 (carboxylic polymer of intrinsic microporosity), giving a homogenous compatible membrane of PAF‐1‐CH₂NH₂—cPIM‐1 with outstanding CO₂ permeability (≈10790 Barrer) and high CO₂/N₂ permselectivity (≈43). This membrane outperforms the counterparts derived from parent PAF‐1 and phenylamine PAF‐1 and possesses superior performance to other relevant membranes for CO₂/N₂ separation. Such a membrane can selectively and stably separate CO₂ from N₂ in a simulated flue gas mixture, demonstrating its huge potential in carbon capture.