NiCo nanoalloy encapsulated in graphene layers for improving hydrogen storage properties of LiAlH 4

Abstract

NiCo nanoalloy (4-6 nm) encapsulated in grapheme layers (NiCo@G) has been prepared by thermolysis of a 3D bimetallic complex CoCo[Ni(EDTA)] 2 ·4H 2 O and successfully employed as a catalyst to improve the dehydrogenation performances of LiAlH 4 by solid ball-milling. NiCo@G presents a superior catalytic effect on the dehydrogenation of LiAlH 4. For LiAlH 4 doped with 1 wt% NiCo@G (LiAlH 4-1 wt% NiCo@G), the onset dehydrogenation temperature of LiAlH 4 is as low as 43 °C, which is 109 °C lower than that of pristine LiAlH 4. 7.3 wt% of hydrogen can be released from LiAlH 4-1 wt% NiCo@G at 150 °C within 60 min. The activation energies of LiAlH 4 dehydrogenation are extremely reduced by 1 wt% NiCo@G doping.