Gaseous N2 has been efficiently introduced in the hollow cavities of aligned CNx nanotubes (15–80 nm od) by pyrolysing a jet (spray) solution of Fe(C5H5)2 and PhCH2NH2 in an Ar atmosphere at 850 °C; the aligned material consist of large arrays (2.5 cm2) of CNx (x < 0.05) ‘bamboo-like’ nanotubes (x nanotubes; these results demonstrate for the first time, that CNx nanotubes can be used to fabricate gas storage components.