Atomic‐Level Nanoconfinement Strategy for Self‐Standing Permselective Membranes Enabling Precise Recognition of CO 2 in Multiphase Pollutants

Abstract Atomic‐level nanoconfinement strategy reconfigures spatial and potential fields with single‐atom precision, thereby endowing functional membranes with efficient gas molecule recognition and selective transport capabilities. Herein, nanoconfined self‐standing permselective membranes (NSPMs) are engendered by atomic‐level regulation of cobalt(II) sites within the adsorption‐active layer of conjugated microporous polymers (CMPs), followed by in situ interfacial covalent cross‐linking at nanosized templates. Unlike conventional single‐target membranes, NSPMs synergistically integrate angstrom‐scale precision pore space partitioning (PSP) with atomically dispersed open metal sites (OMSs), thereby generating continuous positive localized electric field channels. This unique architecture confers both precise carbon dioxide (CO 2 ) recognition and efficient particulate matter (PM) purification. The atomic‐level nanoconfinement strategy enables precise partitioning of macropores while concurrently enhancing specific surface area, which further creates binding sites for selective adsorption of CO 2 over methane (CH 4 ) and nitrogen (N 2 ). Featuring the matched spatial partitioning and customized active sites, the atomic‐level cobalt(II) sites NSPM (Co‐NSPM) deliver 99.3% PM 0.3 removal efficiency even in high‐humidity environments, large CO 2 adsorption capacity (3.37 mmol g −1 ), and ultrahigh separation selectivity (CO 2 /N 2 = 230; CO 2 /CH 4 = 75). The proposed atomic‐level nanoconfinement strategy synergistically integrates size‐sieving, electrostatic adsorption, and molecular recognition mechanisms, effectively evading performance degradation or selectivity loss induced by multiphase pollutants cross‐interference in complex environments.