Precise molecular sieving using metal‐doped ultramicroporous carbon membranes for H₂ separation

Blue hydrogen produced from fossil fuels is recognized as a promising large‐scale technology for realizing the hydrogen economy. Membrane‐based separation is emerging as a viable alternative to traditional hydrogen purification technologies. Here, we present a facile strategy for fabricating carbon molecular sieve (CMS) hollow fiber membranes containing uniformly dispersed palladium (Pd) nanoparticles. The Pd nanoparticles, anchored in the carbon strands of CMS membranes, induced the carbon matrix toward a more ordered structure arrangement through a synergistic effect of entropy‐driven size exclusion and acceleration of graphitization. As a result, the doped Pd nanoparticles facilitated the formation of ultramicropores <3.3 Å in the CMS membranes, which enabled a precise molecular sieving ability between H 2 and CO 2 with H 2 /CO 2 selectivity up to 247. Furthermore, the membrane presented good mixed gas separation performances and was stable for over 250 h under simulated harsh industrial conditions.