Hydrogen adsorption on and solubility in graphites

1H NMR study of hydrogen stored in activated carbon powder prepared by mechanical milling

“…These peaks and the peak near 2 ppm suggest that there are at least three hydrogen components in hydrogenated milled AC. The existence of these three hydrogen components agrees well with the three peaks in the deuterium desorption curves for graphite [12] and the three hydrogen retention sites in the graphite lattice [14].…”

Hydrogen in the mechanically prepared nanostructured graphite

“…The mechanical milling results in the formation of dangling carbon bonds in graphite, 11,12,20 and thus the relative ratio of the CH x covalent bonds will increase if the milling was performed under hydrogen atmosphere. The relative ratio should be reduced from the viewpoint of reversible hydrogenation reaction, and for this purpose, we are now pre- …”

Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy Analysis of Hydrogenated Nanostructured Graphite Prepared by Mechanical Milling

“…Since it is widely accepted that defects (broken bonds) must be involved for hydrogen trapping in graphitic materials, the high hydrogen retention of this material was greeted with surprise. Thermal desorption spectroscopy (TDS) exhibited two distinctive peaks with the mass number of 2, one broad peak ranging from 600 to 800 K and a sharp peak at $1000 K. Although much TDS data has been accumulated on hydrogenated graphitic materials, [6][7][8][9][10][11] the two peaks characteristic of nanostructured graphite are very different from those found in TDS of other hydrogenated graphitic materials. Recent reports 12,13) confirmed that nanostructured graphite prepared in the same manner but with ceramic vessels and balls actually showed very different TDS profiles; namely, only a broad spectrum ranging from 750 to 1200 K. They have suggested that a small amount of iron contamination during milling played an important role in the hydrogen absorption/desorption properties of this material.…”