Hydrogen Storage Investigation on Nanotube, Graphene and Organo-metallic Complexes

New materials and methods for storing hydrogen at high gravimetric and volumetric densities are required because of the widely use of hydrogen for clean fuel. With exceptionally high surface areas, porous materials based on carbon have recently emerged as some of the most promising candidate materials. Here I reviewed our former work on hydrogen storage based on several kinds of organometallic Complexes. Maximum capacities of the hydrogen storage in organometallic compounds consisting of Co and Ni atoms bound to C$_{\mathrm{m}}$H$_{\mathrm{m}}$ ring were found 3.48 wt {\%} and 3.49 wt {\%}, respectively; for the structures having a transition metal (TM) Co and Ni inserted in C$_{\mathrm{m}}$H$_{\mathrm{m}}$ ring, the maximum number of H$_{2}$ molecule bound to the inserted-type CoC$_{\mathrm{m}}$H$_{\mathrm{m}}$ and NiC$_{\mathrm{m}}$H$_{\mathrm{m}}$ complexes is three, and the largest hydrogen storage density is 5.13 wt {\%} and 3.49 wt {\%} for CoC$_{4}$H$_{4}$ and NiC$_{4}$H$_{4}$, Meanwhile, the ionic (C$_{4}$H$_{4}^{+}$ and C$_{5}$H$_{5}^{+})$ improves the capability of hydrogen storage and makes all H$_{2}$ adsorbed to the charged compounds in molecular form. With the CH$_{3}$ ligand bound to the compounds, the adsorption energy of H$_{2}$ decreases to an ideal range, and stability of the compounds are improved. At last, the hydrogen adsorption properties on the complex structures TiRH$_{7}$Si$_{8}$O$_{12}$ are investigated, and the kinetic stability when H$_{2}$ was added to organometallic compounds is also discussed by analyzing HOMO-LUMO gaps. Here we also mentioned our results of hydrogen storage based on nanotubes and graphene.