Synthesis of Porous,Nitrogen‐Doped Adsorption/Diffusion Carbonaceous Membranes for Efficient CO2 Separation

A porous, nitrogen‐doped carbonaceous free‐standing membrane (TFMT‐550) is prepared by a facile template‐free method using letrozole as an intermediate to a triazole‐functionalized‐triazine framework, followed by carbonization. Such adsorption/diffusion membranes exhibit good separation performance of CO₂ over N₂ and surpassing the most recent Robeson upper bound. An exceptional ideal CO₂/N₂ permselectivity of 47.5 was achieved with a good CO₂ permeability of 2.40 × 10⁻¹³ mol m m⁻² s⁻¹ Pa⁻¹. The latter results arise from the presence of micropores, narrow distribution of small mesopores and from the strong dipole–quadrupole interactions between the large quadrupole moment of CO₂ molecules and the polar sites associated with N groups (e.g., triazine units) within the framework.