High‐Performance Hybrid CMS Membranes Development via Synergistic Pore Tailoring and Sulfur‐Doping

ABSTRACT Precisely tailoring the micro‐structure of hybrid carbon molecular sieve (HCMS) membranes is of critical importance to enhance their gas separation performance. Herein, an organic acid, methanesulfonic acid (MSA), was employed as a porogen and dopant of sulfone in CMS membranes. MSA acted as a porogen to generate abundant micropores (enhancing diffusivity), meanwhile the presence of MSA turned the pore structure (promoting selectivity). Theoretical calculations confirmed that the S‐doped pore environment exhibited superior affinity toward CO ₂ . The resulting 6FDA‐TMPD/MSA‐5‐500 HCMS membrane displayed an ultra‐high CO ₂ permeability of 10557.6 Barrer (representing a ∼150‐fold enhancement over its precursor) and a CO ₂ /CH ₄ selectivity of 29.1, surpassing the latest Robeson upper bound. Moreover, the MSA‐mediated cross‐linking structure promoted the formation of more ordered Langmuir domains and reduced the d‐spacing as well as ultramicropore sizes. Concurrently, precise tuning of carbonization parameters further enriched the population of ultramicropores within the size range between H ₂ (2.9 Å) and CO ₂ (3.3 Å). Specifically, the 6FDA‐TMPD/MSA‐5‐700 HCMS membrane presented a H ₂ /CH ₄ selectivity of 539.0 coupled with a H ₂ permeability of 2421.9 Barrer. This work synchronously modulates the pore structure and surface chemical properties of CMS membranes, providing new references for the preparation of high‐performance CMS membranes for gas separation.