NMR Study of LiBH_4 with C_(60)

LiBH_4 doped with 1.6 mol % well-dispersed C_(60) is studied with solid-state nuclear magnetic resonance (NMR). Variable-temperature hydrogen NMR shows large changes between the data upon first heating and after exposure to 300 °C. After heating, a large fraction on the order of 50% of the hydrogen signal appears in a motionally narrowed peak, similar to a previous report of LiBH_4 in a porous carbon aerogel nanoscaffold. Magic-angle spinning (MAS) NMR of ^(13)C in a ^(13)C-enriched sample finds the C_(60) has reacted already in the as-mixed (unheated) material. Dehydriding and rehydriding result in further ^(13)C spectral changes, with nearly all intensity being found in a broad peak corresponding to aromatic carbons. It thus appears that the previously reported improved dehydriding and rehydriding kinetics of this material at least partially result from in situ formation of a carbon framework. The method may offer a new route to dispersal of hydrides in carbon support structures.