NBEXP0009

=NBEXP0009 — XRD analysis of graphite, graphene oxide, graphene/TiO2 & UV-illuminated graphene oxide=

=Objective=

To show that
 * 1) graphite is oxidised to graphene oxide
 * 2) graphene oxide is reduced to graphene with TiO2 illumination
 * 3) and to determine whether graphene oxide can be reduced using UV illumination alone

=Background=

Highly-ordered pyrolytic graphite (HPOG)exhibits a narrow, well-defined peak at 25-30° (e.g. 26.495° [1]), corresponding to the c-axis d-spacing of 0.34nm[2] (c axis = axis normal to layers). Disordered graphite will exhibit a peak around the same angle but broader.



Fully-oxidised graphene oxide should exhibit no peak at ~26°, rather, it should have a broad peak at ~11.8°, corresponding to a larger d-spacing of ~0.75nm [3] (the additional width is due to the functional groups). Reduced graphene oxide should exhibit a similar pattern to that of graphite, although it has been reported that functionalised graphene sheets exhibit a completely amorphous spectrum (i.e. no peaks) [2]

Anatase nanoparticle TiO2 exhibits peaks at around 25 (single), 38 (triplet), 48 (single) & 55 (doublet). [4]

So, we should expect these peaks to appear along with those from graphene in the graphene/TiO2 sample.

=Samples=

=Procedure=

=Results=

=Discussion=

=Conclusion=

=References=

[1] Eunkyung Kim, Ilwhan Oh and Juhyoun Kwak. 'Atomic structure of highly ordered pyrolytic graphite doped with boron', Electrochemistry Communications, 3, 608-612 (2001) [2] Michael J. McAllister, Je-Luen Li, Douglas H. Adamson et. al., 'Single Sheet Functionalized Graphene by Oxidation and Thermal Expansion of Graphite', Chem. Mater. 2007, 19, 4396-4404. [3] Guoxiu Wang, Juan Yang, Jinsoo Park et. al. 'Facile Synthesis and Characterization of Graphene Nanosheets', J. Phys. Chem. C 2008, 112, 8192–8195 [4] A.L. Castroa, M.R. Nunesa, A.P. Carvalho et. al., Synthesis of anatase TiO2 nanoparticles with high temperature stability and photocatalytic activity, Solid State Sciences, 10, 602-606 (2008).

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