Covalent organic framework (COF) membranes have emerged as promising candidates for hydrogen purification due to their tunable pore sizes and robust structures. However, achieving high selectivity and permeability simultaneously remains a challenge due to the inherent pore size distribution of COF materials. In this study, we fabricated two distinct COF membranes, TpPa-1 and TpTGCl, with pore sizes of 1.8 nm and 0.39 nm, respectively, using tailored synthesis methods. The TpTGCl membrane, synthesized via room temperature interfacial polymerization and vacuum-assisted filtration, exhibits an ultrathin nanosheet structure with an interlayer π–π stacking distance of 0.33 nm. This unique architecture, combined with its affinity for CO2 adsorption, enables exceptional hydrogen separation performance, achieving a H2/ CO2 selectivity of 52.5 and a H2 permeability of 3.49 × 10– 7 mol m− 2 s− 1 Pa− 1. Molecular dynamics simulations confirmed the steric hindrance effect as the primary mechanism for the selective permeation of hydrogen. The TpTGCl membrane effectively sieves larger gas molecules ( CO2, N2, CH4, etc.) without the need for material modification or excessive membrane thickness. This study demonstrates the potential of COF membranes with tailored pore sizes for high-performance hydrogen purification and offers valuable insights for the development of advanced separation technologies.

Nonporous materials have nano-sized pores. High specific surface area and size and shape selectivity (size and shape Selectivity) are the most important features of these materials that have led to their widespread use in various industries, such as catalysts, water treatment and separation of pollutants. The development of properties and applications of these materials depends on the fabrication of nanoporous materials with optimal and controlled structures. In this paper, porous nanostructures and supermolecular chemistry are introduced in detail. Then, a number of common nanoporous materials, such as activated carbon, metal–organic frameworks and zeolites, then various types of mineral and organic nanoporous materials as well as methods of synthesis, characterization and applications of these materials will be studied in detail.