  Nanocomposites comprising of high surface area adsorption materials and
nanosized transition metals have emerged as a promising strategy for hydrogen
storage application due to their inherent ability to store atomic and molecular
forms of hydrogen by invoking mechanisms like physisorption and spillover
mechanism or Kubas interaction. The potential use of these materials for both
transport and stationary applications depends on reaching the ultimate storage
capacity and scalability. In addition to achieving good hydrogen storage
capacity, it is also vital to explore novel and efficient synthesis routes to
control the microstructure. Herein, a direct and simple thermal decomposition
technique is reported to synthesize carbon-based nanocomposites, where nickel
nanoparticles are dispersed in a porous carbon matrix. The structure,
morphology, composition and nature of bonding in the samples were investigated
using transmission electron microscopy, scanning electron microscopy, energy
dispersive spectroscopy, X-ray diffraction and Raman spectroscopy.
Sorption-desorption isotherms were used to study the hydrogen storage capacity
of the nanocomposites at a moderate H2 pressure of 20 bar. Among the various
nanocomposites examined, the best obtained storage capacity was 0.73 wt.%
(against 0.11 wt.% for pure carbon sample) at 298 K with reversible
cyclability. It is shown that the uniform dispersion of catalytic nanoparticles
along with a high surface area carbon matrix helps in the enhancement of
hydrogen storage capacity by a factor of 6.5 times over pure carbon.
