Oxidation-aided cap-removal of chemical vapor deposition-prepared single-wall carbon nanotubes

The cap-removal conditions of chemical vapor deposition-prepared single wall carbon nanotube (SWCNT) bundles were optimized via air oxidation at different temperatures. We determined specific surface areas (SSAs) of the SWCNT oxidized at different temperatures from N 2 adsorption isotherms with the aid of the subtracting pore effect (SPE) method enabling evaluation of the SSA of microporous carbons without overestimation. The oxidation of SWCNT at 773 K gave the maximum SSA of 1840 m 2 g −1 . We chose the oxidation temperature of 773 K for the optimum oxidation for the cap-removal without serious crystallinity damages. The SSAs from the SPE method of the SWCNT bundles before and after oxidation at 773 K almost coincided with the geometrically evaluated SSAs of SWCNT with and without caps, confirming the selective removal of caps from SWCNT through the oxidation at 773 K. TEM and Raman spectroscopic examination guaranteed the well-crystalline state of the SWCNT bundles oxidized at 773 K, as suggested from N 2 adsorption measurements.