The hydrogen storage capacity of Sc atoms decorated porous boron fullerene B40: A DFT study

The binding energy (Eb) of the Sc atom to the B6 and B7 rings of B40 is high to 4.61 eV and 5.24 eV respectively, which are much larger than the experimental cohesive energy of bulk Sc (3.90 eV/atom) and that of the Sc atom binding on the surface of B80 (3.60 eV), therefore, the problem of metal aggregative to form Scn cluster on the surface of B40 is expected to be overcome, and the Sc decorated B40Sc6 structure will be stable for designing a recyclable hydrogen material. The average adsorption energy and consecutive adsorption energy reveal that each Sc atom can adsorb five hydrogen molecules, inconsistent with that calculated by the 18-electron rule. Moreover, the calculated desorption temperature and molecular dynamic simulation indicate that the B40(Sc-5H2)6 structure is easy to desorb H2 molecules. The HGD of the bulk [B40(Sc-5H2)4]4 is 6.18 wt%, a little smaller than that for B40(Sc-5H2)6 (8.3%), however still exceeding the 5.5 wt% at 2017 specified by the US department of energy (DOE). Therefore, the stable B40Sc6 structure can be applied as one candidate for reversible hydrogen storage materials under near-ambient conditions.329