Hydrogen Storage in Novel Carbon-based Nanostructured Materials

One of the biggest challenges facing a future hydrogen economy is that of onboard vehicular hydrogen storage, for which novel carbon-based nanostructured materials have emerged as potential candidates. Towards this end, we present the synthesis and characterization of ``bucky dumbbell,'' a new organometallic compound comprised of two buckyballs complexed to a central iron atom. This new compound has been characterized using both $^{13}$C solid-state NMR and Raman spectroscopy, and electron spin paramagnetic resonance spectroscopy reveals the presence of Fe$^{3+}$. Temperature-programmed desorption has revealed a new hydrogen binding site via the appearance of a peak centered at approximately -50 \r{ }C, indicating the hydrogen is stabilized at a temperature significantly above that expected for physisorption but still lower than that of C-H bond formation. Comparison with C$_{60}$ under the same hydrogen exposure and heating conditions shows almost no hydrogen adsorption, and the exact binding energy (or desorption activation energy, E$_{d})$ for the bucky dumbbell shows an enhanced value of $\sim $6.2 kJ/mol. Initial volumetric analyses conducted at 77K and 3 bar show a storage capacity of $\sim $0.4 wt{\%}. The synthesis and analysis of other novel fullerene-based organometallic hydrogen complexes will also be discussed.