Intercalated hydrogen in nanostructured graphite studied by electron energy-loss spectroscopy and molecular orbital calculations

Hydrogen loosely trapped between graphitic basal planes in hydrogenated nanostructured graphite was detected by the change in the relative intensity ratio of the π* and σ* peaks of the C K-edge in electron energy-loss spectroscopy (EELS). The experimental spectral change was explained by model calculations of intercalated hydrogen in graphitic sheets, using an ab initio molecular orbital (DV-Xα) method. The present result suggests that in some cases the conventional method to estimate the sp2/sp3 ratio of graphitic materials by EELS needs to be cautiously applied.