Selective Hydrogen Transport Through Polymeric Fullerene Nanosheet Membranes

Lamellar membranes, assembled from two-dimensional (2D) nanosheets, have attracted intensive attention for molecular and ion sieving due to their tunable interlayer channels and ultrathin selective layers. However, molecular transport in conventional lamellar membranes usually occurs through interlayer galleries whose dimensions vary with stacking, limiting ångström-scale control over selectivity. Therefore, developing a novel lamellar membrane with ångström-scale in-plane pores is highly desirable. In an idealized qTP lattice, four-directionally connected fullerene cages define periodically distributed apertures that converge from an approximately 5.87 Å entrance to a 3.11 Å waist. Upon assembly, the constriction regions can discriminate by size, while their converging entrances and the intersheet galleries govern molecular access and transport resistance through the in-plane apertures. The resulting polymeric fullerene nanosheet membrane exhibits an H₂ permeance of 3896 ± 107 GPU and an H₂/CO₂ separation factor of 88.5 ± 5.9 for the separation of an equimolar H₂/CO₂ mixture at 303.15 K and a total feed pressure of 100 kPa. The separation performance remains stable over 200 h of operation. This study establishes topology-encoded pore geometry as a design principle for integrating short selective pathways with ångström-scale molecular discrimination in lamellar membranes.