Hydrogen Storage in Nanosize Diamond Powder-Surface Modified by Naf

摘要

Hydrogen based fuel cells in automobiles may offer the vital solution to the world's socio-political dependence on oil. However a safe and efficient on-board hydrogen storage system is necessary for commercialization of fuel cell based automobiles. Storing of hydrogen in solid adsorbents is one of the options for on-board storage. According to the US Department of Energy an adsorbent should have hydrogen storage capacity of 6.5 wt% for commercial applications. Several researchers have reported that carbon based adsorbents, particularly carbon nanotubes, carbon fibers, single wall nanotubes, are most promising for achieving the US Department of Energy's targeted capacity for hydrogen storage. A wide range of adsorption capacity for hydrogen reported on these adsorbents. However, Schimmel et al. concluded that hydrogen storage capacity of carbon based materials including carbon nanotubes, nanofibers, and single wall carbon nanotubes depended on the surface area of the individual materials and the maximum storage capacity was found to be 2% only at low temperatures. The preliminary work by Ghosh, Prelas and their co-workers with diamond plates and nanophase diamond powder showed promise for storing hydrogen on nanophase diamond. They also noted that the storage capacity may be enhanced if the diamond surface is charged. The objective of this work was to treat the diamond surface with a fluorine compound. Fluorine can terminate the bonds on the diamond surface to attract hydrogen and keep it weakly bound to the surface.