Recent calculations [PRL 94, 175501 (2005)] suggest transition metal-decorated nanostuctures as potential high-capacity hydrogen storage medium READ FULL STORY..

		There have been a great number of reports on the search of new routes to engineer nanomaterials so that (1) they dissociate H2 molecules into H atoms and (2) reversibly adsorb hydrogen molecules at ambient conditions. Much effort has been focused on the engineering of carbon-based materials such as nanotubes and transition metal hydrides without success. It is found that while hydrogen-carbon interaction is too weak, the metal-hdyrogen interaction is too strong for room temperature reversible storage. Here we show a novel way to overcome this difficulty by forming artificial metal-carbides on nanotubes/C60 molecules! From accurate first-principles calculations, we show that a single Ti-atom coated on a SWNT/C60 can strongly adsorb up to four hydrogen molecules. The hydrogen-metal bonding is an unusual combination of chemi- and physi-sorption, an essential ingredient needed for reversible hydrogen storage medium near room temperature. Remarkably, this adsorption occurs with no energy barrier.
		At large Ti coverage we show that a (8,0) SWNT and C60 can store hydrogen molecules up to 8-wt%, exceeding the minimum requirement of 6-wt% for practical applications. Finally, we present high temperature quantum molecular dynamics simulations showing that these systems are stable and indeed exhibit associative desorption of H2 upon heating, another requirement for reversible storage.These results are quite remarkable, unanticipated, and to the best of our knowledge, the first-demonstration of hydrogen-metal complex formation containing FOUR H2 molecules. SEE FULL STORY..