Oxidation and porosity evaluation of budlike single-wall carbon nanohorn aggregates

Budlike single-wall carbon nanohorns (SWNHs), being capped hollow materials, were oxidized by heating in oxygen to produce nano-order windows in the walls. The opening of budlike SWNHs was studied with transmission electron microscopy and nitrogen adsorption at 77 K. The adsorption isotherms show development of the porosity with increasing the temperature of the SWNHs oxidation. Thus, the micropore volume of SWNH after oxidation in O-2 at 693 K increases three times. The adsorption analysis of both substructures, formed by the nanohorn interstices and their internal cavities, is discussed. The oxidation does not change the size and shape of the budlike SWNH bundles. It is an effective way to produce SWNHs with a big micropore volume.