Accelerating NH3 Transport Through Nanoconfined Functionalized Ionic Liquid in Graphene Oxide Membrane

Graphene oxide (GO) holds great promise for fabricating high-flux separation membranes, yet its inherent interlayer defects often compromise precise molecular sieving, particularly for challenging separations such as selective ammonia (NH 3 ) capture and purification. In this work, a functionalized ionic liquid ([DBEAH][NTf 2 ]) with protic hydrogen and hydroxyl groups as NH 3 -interactive sites is designed and confined within GO interlayers via hydrogen bonding and electrostatic interactions, thereby constructing tailored pathways for selective NH 3 transport. The incorporated [DBEAH][NTf 2 ] not only modulates the interlayer spacing of GO but also modifies the nanochannels to create an NH 3 -affinitive environment for precise recognition and separation of NH 3 . The resulting IL-confined GO membrane achieves an outstanding combination of high NH 3 permeance of 682.17 GPU and ultrahigh ideal NH 3 /N 2 selectivity of 1488.41 in single-gas tests. Under mixed‑gas conditions (50/50 vol%, NH 3 /N 2 ), the membrane maintains a high NH 3 permeance of 493.82 GPU and an NH 3 /N 2 separation factor of 248.34. Theoretical simulations further confirm that the confined [DBEAH][NTf 2 ] facilitates rapid and selective transport of NH 3 while effectively blocking N 2 , providing a mechanistic understanding of the enhanced separation performance. This study offers a feasible strategy for designing 2D membranes with simultaneously high permeance, selectivity, and stability for NH 3 separation applications.