Direct thermal fluorination of single wall carbon nanohorns

Single wall carbon nanohorns (SWNHs) were fluorinated to form more attractive nanohorns that have characteristic structural and adsorptive properties. Nitrogen adsorption, XPS, and TEM studies elucidated the surface states and the morphologies of fluorinated SWNHs (F-SWNHs). The XPS results of F-SWNHs showed that the nature of C-F bonds changed from semi-ionic to covalent with an increase in the fluorination temperature. The N-2 adsorption isotherm indicated that the total amount of N-2 adsorption on SWNHs fluorinated at 303 and 373 K was smaller than that of pristine SWNHs. After fluorination at 473 K, nanoorder windows were produced on the sidewalls of SWNHs without a change in the shape of each horn and aggregate. Therefore, the SWNHs fluorinated at 473 K can adsorb N-2 molecules on the internal surfaces of nanohorns through the nanowindows.