Fe 3 O 4 nanoclusters highly dispersed on a porous graphene support as an additive for improving the hydrogen storage properties of LiBH 4 .

Fe 3 O 4 nanoclusters anchored on porous reduced graphene oxide (Fe 3 O 4 @rGO) have been synthesized by a one-step hydrothermal route, and then ball milled with LiBH 4 to prepare a hydrogen storage composite with a low onset dehydrogenation temperature, and improved dehydrogenation kinetics and rehydrogenation reversibility. The LiBH 4 -20 wt% Fe 3 O 4 @rGO composite begins to release hydrogen at 74 °C, which is 250 °C lower than for ball-milled pure LiBH 4 . Moreover, the composite can release 3.36 wt% hydrogen at 400 °C within 1000 s, which is 2.52 times as high as that of pure LiBH 4 . Importantly, it can uptake 5.74 wt% hydrogen at 400 °C under 5 MPa H 2 , and its hydrogen absorption capacity still reaches 3.73 wt% after 5 de/rehydrogenation cycles. The activation energy ( E a ) of the hydrogen desorption of the composite is decreased by 79.78 kJ mol -1 when 20 wt% Fe 3 O 4 @rGO is introduced into LiBH 4 as a destabilizer and catalyst precursor, showing enhanced thermodynamic properties. It could be claimed that not only the destabilization of Fe 3 O 4 , but also the active Li 3 BO 3 species formed in situ , as well as the wrapping effect of the graphene, synergistically improve the hydrogen storage properties of LiBH 4 . This work provides insight into developing non-noble metals supported on functional graphene as additives to improve the hydrogen storage properties of LiBH 4 .