Carbon dioxide adsorption on H$_{2}$O$_{2}$ treated single-walled carbon nanohorns*

Carbon nanohorns are closed single-wall structures with a hollow interior. Unlike SWNTs, which assemble into cylindrical bundles, nanohorns form spherical aggregates. In our experiments we used dahlia-like carbon nanohorn aggregates. Our sample underwent treatment with H$_{2}$O$_{2}$ which opened access to the interior spaces of the individual nanohorns. We measured carbon dioxide adsorption at several temperatures between 167 and 195 K. We calculated the isosteric heat as a function of loading, and the binding energy values for CO$_{2}$ on the nanohorn aggregates from the isotherm data. Results on the H$_{2}$O$_{2}$-treated nanohorns will be compared with those obtained on other carbon substrates. We have also determined detailed equilibration profiles for CO$_{2}$ adsorption on the nanohorn aggregates; these results will also be presented.