This document discusses materials for hydrogen storage and some of the challenges. It notes that hydrogen is not an energy source itself but an energy carrier, and currently it is stored as either high-pressure gas or cryogenic liquid. Solid materials could provide an alternative storage method. Sorbent materials like carbon nanotubes and metal-organic frameworks can store hydrogen at low temperatures but have low storage capacities at room temperature. Complex hydrides can store more but are heavy, expensive, and only work at high temperatures. Nanostructured materials show potential through properties unlike bulk materials, but have yet to emerge as practical solutions and require more research into catalysts, intermediate phases, and kinetics.

1. Materials for H2 storage
Presented by
Mahfooz Alam
(17ETMM10)
#Ref: Materials for Hydrogen Storage: Past, Present, and Future; by Puru Jena; J. Phys. Chem. Lett., 2011, 2 (3),
pp 206–211,DOI: 10.1021/jz1015372

2. Benjamin Franklin once wrote “...in this world nothing can said to be
certain but death and taxes.” Well, there is at least one more thing that
can be said to be certain in this world, the limited supply of fossil fuels
Two-thirds of the oil used in the United States goes to meet the
demands of the transportation industry

3. Problems with H2
• Hydrogen is not an energy source but rather an energy carrier. It is
not freely available in nature and needs to be produced from water or
other organic compounds.
• Currently, hydrogen is stored either in high pressure tanks or in liquid
form(critical temp=33K) in cryogenic tanks. The energy density of
hydrogen even at 690 bar or in liquid form(at 20K) is 4.4 and 8.4 MJ/L
where that of gasoline is 31.6 MJ/L.(1ltr to 4ltrs).
• The alternative is to use solid materials for hydrogen storage. It has
been known for more than a century that hydrogen can be stored
reversibly in metals such as Pd. Unfortunately, these metals are heavy
and are not suitable for commercial automotive applications

4. In terms of the strength of hydrogen bonding:
(a)sorbent materials (meV)
(b)Complex hydrides (2-4eV)
(c)Nano structured materials (0.1-0.8eV)

5. Sorbent materials
• Carbon-based materials such as nanotubes, fullerenes, graphene,
mesoporous silica, metal-organic frameworks (MOFs) etc.,
• CNTs’ exhibit promising hydrogen storage capacities at 77 K, only less
than 1 wt % of hydrogen can be stored at 298 K and 100 atm of
pressure.
• Porous aromatic frameworks (PAFs) with diamond-like structure has
been proposed that possess higher gravimetric hydrogen density than
COF-102, namely, it can store 6.53 wt % hydrogen at 298 K and 100
bar.

6. Complex hydrides
2100C, 3.7wt%
2500C, 1.9wt%
• These are heavy
• Expensive
• Works at high temperatures
only
• Some are not reversible
Clathrate hydrates: (H2)4CH4
(referred to as H4M), with 33.4%
molecular hydrogen by mass or 50%
total hydrogen if one includes the
four hydrogen atoms within each
methane molecule.

7. Functionalized Nanostructures
• Research on nanostructured materials has clearly demonstrated that
reduced size, low dimensionality, and low coordination can lead to
properties that are very different from the corresponding bulk
materials. Because the physics and chemistry of matter at the Nano
scale can be fundamentally altered, considerable research has
focused on the role that nanostructures can play in the search for
“ideal” hydrogen storage materials.
• Transition-metal-doped C60 fullerene can store hydrogen upto 9 wt %
reversibly with favorable kinetics and thermodynamics.
• Theoretical studies showed that Li and Ca atoms supported on C60
and nanotubes do not cluster, and up to 13 wt % hydrogen can be
stored on Li12C60.
• Research is going on….

8. Summary

9. Conclusions
• Nanostructured materials provide opportunities but are yet to
emerge as practical materials.
• Much research still needs to be done to identify appropriate catalysts,
study the existence of stable intermediate phases and their crystal
structure, and understand the kinetics.
“….water will furnish an inexhaustible source of heat and light, of an intensity of which
coal is not capable...When the deposits of coal are exhausted we shall heat and warm
ourselves with water. Water will be the coal of the future.” said Jules Verne in “The
Mysteriuos Island”

10. Thank you all
Questions?