Crystalline metal-organic frameworks (MOFs) exhibit enormous potential application in gas separation, thanks to their highly porous structures and precise pore size distributions. Nevertheless, the inherent limitations in mechanical stability of crystalline MOFs cause challenges in processing MOF powders into bulky structures, particularly for membrane filtrations. Melt-quenched MOF glasses boast excellent processability due to liquid-like properties. However, the melting process diminishes the inherent porosity, leading to reduced gas adsorption capacities and lower gas diffusion coefficients. In this work, we demonstrated that enhancing the porosity of MOF glasses is achievable through topological engineering on the crystalline precursors. Crystalline zeolitic imidazolate frameworks (ZIFs) with large 12-membered rings pores, including AFI and CAN topology, were synthesized by using both structure-directing agents and mixed organic ligands. The large pores are partially preserved in the melt-quenched glass as evidenced by high-pressure CO₂ absorption at 3000 kPa. The a_gAFI-[Zn(Im)_1.68(bIm)_0.32] glass was then fabricated into self-supported membranes, which shows high gas separation performance, for example, CO₂ permeance of 3.7 × 10⁴ GPU with a CO₂/N₂ selectivity of 14.8.

The low porosity of metal‐organic framework glass makes it difficult to prepare membranes with high permeability. To solve this problem, we fabricated a series of self‐supported zeolite glass composite membranes with different 4A zeolite loadings using the abundant pore structure of the zeolite. The 4A zeolite embedded in the zeolite glass composite membrane preserved the ligand bonds and chemical structure. The self‐supported zeolite glass composite membranes exhibited good interfacial compatibility. More importantly, the incorporation of the 4A zeolite significantly improved the CO₂ adsorption capacity of the pure a_gZIF‐62 membranes. In addition, gas separation performance measurements showed that the (a_gZIF‐62)_0.7(4A)_0.3 membrane had a permeability of 13,329 Barrer for pure CO₂ and an ideal selectivity of 31.7 for CO₂/CH₄, which exceeded Robeson's upper bound. The (a_gZIF‐62)_0.7(4A)_0.3 membrane exhibited good operational stability in the variable pressure test and 48 h long‐term continuous test. This study provides a method for preparing zeolite glass composite membranes.