Hydrogen in the mechanically prepared nanostructured graphite

Nanostructured graphite was prepared by mechanical milling under hydrogen atmosphere. Several samples obtained after different milling times were systematically examined to get fundamental information about the structures and hydrogen concentrations. After the expansion of the graphite interlayer, the long-range ordering of the interlayer disappears continuously with increasing milling time. The hydrogen concentration reaches up to 7.4 mass % (CH0.95) after milling for 80 h. Judging from the radial distribution function determined by the neutron diffraction measurement, there are two types of deuterium coordinations: deuterium atoms in the graphite interlayers and that with the CDx covalent bonds, respectively. (C) 1999 American Institute of Physics. [S0003-6951(99)01646-0].