Selectively enriching accessible quantum sieving sites in two‐dimensional carbons for D₂/H₂ kinetic separation

Separation of hydrogen isotopes (D 2 /H 2 ) attracts wide interest due to its important applications, such as nuclear fusion. Kinetic quantum sieving‐induced separation over tailored nanoporous solids is a promising method; however, the dynamic separation often shows a transient feature, thus a low D 2 /H 2 selectivity even at temperature below 50 K. Herein, we selectively enriched the accessible quantum sieving (AQS) sites in two‐dimensional carbons by chemically growing a pore‐narrowing layer. The spatial density of such AQS sites is 8.5 times higher than that of commercial carbon molecular sieves. The kinetic selectivity of D 2 /H 2 reached 4.6 at 77 K. Column breakthrough experiments revealed that the dynamic D 2 /H 2 separation was enhanced by such a nanopore design. Aspen simulation indicated that D 2 was enriched to 93.1% within 11 pressure swing adsorption cycles with a 1% D 2 /99% H 2 mixture as feed.