Quantum Molecular Sieving Effects of H₂ and D₂ on Bundled and Nonbundled Single-Walled Carbon Nanotubes

Abstract

The quantum molecular sieving effects of pore-structure-controlled single-walled carbon nanotubes (SWCNTs) for H2 and D2 were evaluated at 20, 40, and 77 K. The adsorption amounts of D2 were larger than those of H2. The lower the adsorption temperature, the greater the difference between the D2 and H2 adsorption amounts. Bundled SWCNTs with interstitial pores of diameter 0.6 nm gave the greatest adsorption difference between D2 and H2 per unit pore volume. Diffusion-dominated behavior was observed in the low-pressure region at 20 and 40 K as a result of lower mobility. Bundled SWCNTs with only interstitial pores provided a significant quantum molecular sieving as a result of strongly interacting potential wells.