Repeatable hydrogen adsorption using nanostructured graphite at room temperature

Repeatable hydrogen adsorption and desorption by nanostructured graphite was confirmed using a high-accuracy volumetric measuring apparatus at room temperature. The nanostructured graphite was prepared from graphite powder using a mechanical milling process at a pressure of 2.0×10−4 Pa. The untreated graphite adsorbed 0.02 wt % of hydrogen, while 0.20–0.25 wt % of hydrogen can be repeatedly adsorbed by the nanostructured graphite. Measurements of the hydrogen adsorption rate at constant pressure and pore-size distribution suggest that the hydrogen molecules are adsorbed through a diffusion process into pores with a diameter less than 1 nm.