On the physics and atomic mechanisms of molecular hydrogen intercalation into graphite nanofibers

The fundamental experimental data obtained in [I.O. Bashkin et al., JETP Lett. 79, 226 (2004)] on three states of hydrogen corresponding to physical sorption (state 1), chemisorption (state 2), and intercalation (state 3) in graphite nanofibers subjected to hydrogenation in H$_2$ at a pressure of 9 GPa and a temperature of 753 K (with subsequent quenching), which led to a hydrogen content of up to 6.3 wt %, have been analyzed in detail using an effective method for processing thermal desorption spectra of hydrogen. In particular, attention is paid to the physics and atomic mechanisms of intercalation of specific molecular hydrogen (state 3) in graphite nanofibers, which is slightly more stable than chemisorbed hydrogen (state 2), and to comparison with the results of analysis and interpretation of the unique data obtained in [C. Park et al., J. Phys. Chem. B 103, 10572 (1999)] on the “super” hydrogen storage in the know-how activated graphite nanofibers.