  A promising material for hydrogen storage at room temperature-Al doped
graphene was proposed theoretically by using density functional theory
calculation. Hydrogen storage capacity of 5.13 wt% was predicted at T = 300 K
and P = 0.1 Gpa with adsorption energy Eb = -0.260 eV/H2. This is close to the
target of 6 wt% and satisfies the requirement of immobilization hydrogen with
Eb of -0.2 ~ -0.4 eV/H2 at ambient temperature and modest pressure for
commercial applications specified by U.S. Department of Energy. It is believed
that the doped Al varies the electronic structures of both C and H2. The bands
of H2 overlapping with those of Al and C synchronously are the underlying
mechanism of hydrogen storage capacity enhancement.
