H₂ Storage Projects

Transition Metal-Decorated Nanotubes and C ₆₀; high-capacity hydrogen storage medium

Introduction | Dissociative Absorption of H2 | Molecular Absorption | 4th top-H2 | The lowest energy isomer | Bonding Mechanism | Does Pt/Pd also work? | MD simulations | High concentration metal-coverages | Ti-decorated C60 | Conclusions

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Molecular absorption of two additional H₂ over Ti-SWNT

Remarkably, it is also energetically favorable for the TiH2 group to complex with additional hydrogen molecules. Fig.1b shows the energy variation as two hydrogen molecules approach the Ti atom; one from each side of the TiH2 group. As in the case of single adsorption, the energy always decreases, first slowly and later very rapidly at which point both hydrogen molecules are strongly attached to the t80TiH2 system. We denote the final product as t80TiH2- 2H2, which is shown in Fig. 1b. The total energy change upon adsorption is about 0.89 eV (i.e. 0.45 eV/H2). Unlike the first adsorption, the two hydrogen molecules are in intact but with a rather elongated bond length of 0.81 Å. This 10% increase is rather reminiscent of the elongated H-H bonds observed in the metal-dihydrogen complexes first synthesized by Kubas.

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