Pore Size Distribution of Single-Walled Carbon Nanotubes

The pore size distributions of bundled single-walled carbon nanotubes were investigated by N 2 adsorption and desorption. It was found that the pore sizes are in two main ranges: <5 nm and 10−100 nm. Furthermore, their heating in an inert gas, CO 2, or H 2 at 800 °C did not change the pore size distribution, even though significant amounts of nanotubes were consumed during the latter two treatments. In contrast, the nitric acid treatment at 70 °C completely changed the pore size distribution, generating an active-carbon-like pore size distribution and a large increase of the total surface area.