Pressure-resilient facilitated CO2 transport in layer-by-layer assembled IL-QD/mGO nanocomposite hollow fiber membranes

Pressure-resilient facilitated-transport membranes are highly desirable for practical CO 2 capture, yet maintaining efficient CO 2 transport under elevated feed pressures remains a major challenge due to the inherent pressure dependence of facilitated transport. Herein, we report a nanocomposite hollow fiber membrane fabricated by infiltrating poly(1-vinyl imidazolium) (PVI) into a polyimide (Matrimid® 5218) hollow fiber support (outer diameter: 650 μm, inner diameter: 510 μm), followed by the layer-by-layer (LbL) assembly of ionic liquid-functionalized quantum dots (IL-QDs) and modified graphene oxide (mGO) via interfacial polymerization. Thermal trimerization of PVI at 150 °C induces the formation of triazine structures, promoting polymer-chain rearrangement that increases free volume and CO 2 sorption sites, thereby facilitating CO 2 dissolution and diffusion. Simultaneously, the alternating LbL architecture enables IL-QDs to function as nanoscale spacers that suppress irreversible π–π stacking of mGO nanosheets, generating continuous CO 2 -philic transport pathways. Benefiting from these synergistic structural effects, the optimized membrane achieved a CO 2 permeance of 16 GPU and a CO 2 /N 2 selectivity of 112 while exhibiting substantially reduced pressure dependence of separation performance. Furthermore, the membrane maintained stable mixed-gas separation performance and excellent long-term operational stability. This work presents a nanostructure engineering strategy for constructing pressure-resilient facilitated-transport hollow fiber membranes, providing new design insights for practical post-combustion CO 2 capture.