Flexible all‐inorganic zeolite‐carbon assembled hollow fiber membranes enable robust <scp> CO ₂ </scp> / <scp> CH ₄ </scp> sieving

Abstract Inorganic crystalline zeolite membranes exhibit unparalleled molecular sieving, yet their intrinsic brittleness severely restricts scalable fabrication. In contrast, polymer‐based mixed‐matrix membranes (MMMs) offer processability but often fail to fully exploit the intrinsic precision of crystalline fillers due to the limited molecular discrimination of the polymer phase. Herein, we report a flexible, monolithic inorganic zeolite‐carbon assembled (ZCA) free‐standing hollow fiber membrane, comprising biomass‐derived continuous carbon molecular sieve (CMS) phases and discrete zeolite phases. The resulting inorganic–inorganic interface sustains high zeolite loadings and creates fast, precise sub‐nanometer transport pathways. We demonstrate efficient CO 2 /CH 4 separation relevant to natural‐gas sweetening, achieving an exceptional CO 2 permeability of 1159.3 Barrer and a CO 2 /CH 4 separation factor of 74.6 under a 25‐bar mixed‐gas feed, outperforming both state‐of‐the‐art MMMs and pure zeolite membranes. Crucially, these all‐inorganic membranes demonstrate remarkable mechanical flexibility and long‐term stability, providing a versatile platform for engineering robust, high‐performance membranes for challenging industrial separations.