Abstract Submitted to the NANOTUBE'02 Workshop:

Single-wall carbon nanohorn (SWNH) was oxidized at different temperatures in order to donate nano-scale windows on the wall of SWNH particle. There are two physical adsorption sites of interstitial and internal nanospaces on oxidized SWNH assemblies. The interaction potential depths of interstitial and internal nanospaces are –1000 and –600 K, respectively. The physical adsorption isotherms of hydrogen on both of SWNH and oxidized SWNH were determined in the wide temperature range of 20 K to 303 K. respectively. Hydrogen adsorption at the boiling temperature (20K) can be explained briefly by the micropore filling mechanism. However, adsorption behavior for supercritical hydrogen showed an anomaly that the hydrogen densities in interstitial and internal spaces were 15 and 10 g L-1 at 303 K and 6.5 MPa. The molecular potential theory cannot explain the above behavior. This behavior is interpreted by the self-locking mechanism. The molecular sieving properties of oxidized SWNH were examined using He, H2, N2, SF6, and C60 having different molecular sizes. The oxidized SWNH showed a clear molecular sieving for these different molecules.