Ozone‐Treated Low‐Temperature Carbonized Membranes for Efficient H ₂ /CO ₂ Separation

Abstract The effective separation of H 2 /CO 2 through membrane technology plays a crucial role in energy‐efficient blue hydrogen production. This work proposes an ozone post‐treatment strategy to enhance the H 2 /CO 2 separation performance of low‐temperature (<600°C) carbonized carbon molecular sieve (CMS) membranes. Reactions occur between ozone and organic groups in the partially carbonized membrane and the pore structure is sharply refined, significantly enhancing molecular sieving capabilities of the resulting membrane. An ozone treated 550°C carbonized CMS membrane achieves a remarkable H 2 permeability of 3805.1 barrer and an exceptional H 2 /CO 2 selectivity of 102.4 under the 50:50 vol% H 2 /CO 2 mixed‐gas feed at 80°C, surpassing almost all the CMS membranes reported to date. The membrane also demonstrates exceptional resistance to physical aging and maintained stable separation performance over extended operation. This study proposes an effective strategy to enhance the gas selectivity of low‐temperature carbonized membranes, opening a new avenue for the development of high‐performance CMS membranes.