Carbon nanotubes and nanoporous activated carbons served as adsorbents for hydrogen storage. Carbon nanotubes were prepared by a special chemical vapor deposition method over a Co-Mo/MgO catalyst, and nanoporous activated carbons were obtained from walnut shells. According to the Fourier transform infrared analysis, oxygenated functional groups were formed on the structures. The X-ray diffraction and scanning electron microscopy results let conclude that the structures were not damaged by the acidic vapor method. The maximum experimental value for adsorption capacity was achieved under elevated pressure. The highest capacity of H-2 adsorption was detected for nitric acid-modified carbon.