Highly Ordered Nanochannels in a Nanosheet‐Directed Thin Zeolite Nanofilm for Precise and Fast CO2 Separation

Abstract Precise molecular and ion separations depend largely on the size and uniformity of the nanochannels in a defect‐free microporous nanofilm. Ordered and perpendicular nanochannels with uniform pore size are assembled into a continuous and defect‐free film by a “gel nuclei‐less” route. The ultrathin (<50 nm) zeolite nanosheets seeding layer induces the formation of defect‐free zeolite nanofilms (500–800 nm) with preferential [100] orientation well‐aligned to the transport pathway. The large‐area and thin silicoaluminophosphate‐34 (SAPO‐34) nanofilm consisting of uniform and straight nanochannels shows a milestone CO 2 permeance of ≈1.0 × 10 −5 mol (m 2 s Pa) −1 and high CO 2 /CH 4 and CO 2 /N 2 selectivities of 135 and 41 in equimolar binary mixtures at room temperature and 0.2 MPa feed pressure, respectively. These results suggest that highly oriented and thin SAPO‐34 nanofilms prepared from nanosheets might have great potential for CO 2 capture from natural gas, biogas, and flue gas.