Dispersion of transition metal atoms in fragmented graphitic shells and hydrogen adsorption therein

We carried out first-principles calculations to study various metal-dispersed graphitic fragments for application to hydrogen storages. Metal-graphitic fragments binding strength and hydrogen-metal binding characteristics were particularly investigated. It was found that structural imperfections and chemical modifications can lead to an enhancement of metal-graphitic fragment binding energy, which is critical to avoid metal aggregation that deteriorates hydrogen uptake. Hydrogen binding characteristics of metal-dispersed graphitic fragments are discussed in terms of atomic and electronic structures. (C) 2007 Elsevier Ltd. All rights reserved.X11sciescopu