Hydrogen storage in novel carbon materials

Keens, SG

Abstract

This thesis examines the potential of C 60 intercalated graphite and titanium oxide
'decorated' graphite as sorbing hydrogen storage media.
Initially, various types of natural flake graphite were examined and characterised with
X-ray diffraction and electron microscopy techniques. Each type was assessed for
suitability for modification by considering impurities, crystal structure and internal
strain. Samples of increased-surface-area exfoliated graphite were then produced as
an initial template for surface modification techniques, and a sample against which to
compare gas-sorption characteristics.
C60 intercalated graphite was produced in order to assess whether fullerenes might be
used to create spacing within graphitic structures to maximise surface area and
increase energies of adsorption at sites around the C60 molecule. Samples were made
via a sublimation method, depositing C60 molecules onto surfaces where it was
subsequently inaccessible to its solvents. Titanium oxide coated materials were
created via a wet chemistry route followed by thermal decomposition, in order to
examine whether this material plays a role in hydrogen uptake via 'spillover'
catalysis reported to be caused by palladium/titanium oxide deposits upon surfaces.
Each sample created was characterised using X-ray diffraction, electron microscopy
and gas-sorption techniques; its apparent density determined by argon displacement,
and then assessed for specific nitrogen BET surface area and hydrogen uptake at
cryogenic temperatures. Although the methods of creating the C 60 intercalated
samples proved detrimental to the material's surface area, it was found that the
hydrogen surface sorption capability (uptake per unit surface area) was almost
doubled. However, hydrogen uptake was effectively negated by titanium oxide
surface depositions even though its surface area was increased. Future work is
planned to further investigate the C 60 intercalated material.

Citation

Keens, S. Hydrogen storage in novel carbon materials. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2009