Effect of ozonolysis on the pore structure, surface chemistry, and bundling of single-walled carbon nanotubes

An ozonolysis protocol has recently been developed that cannot only purify nanotubes but also achieve rational spatial and molecular control over chemical derivatization in single-walled carbon nanotubes (SWCNTs). Ozonolysis likely opens end caps and introduces holes into the sidewalls of tubes, which may occur through an oxidation of carbon atoms located on the nanotube surface, resulting in the formation of oxygen-containing functional groups. Overall, it was demonstrated by analysis of nitrogen adsorption and TGA/DTG that the total surface area, micropore volume, and mesopore volume of SWCNTs depend on several, intertwined factors including the degree of purity, surface functionality, density of surface groups, as well as the state of aggregation of the carbon tubes. Hydrogen bonding in these systems plays a role too. Data suggest that complete removal of surface functionalities would lead to a greater total surface area and higher micropore volume.