Abstract:
In recent years, terrorism has become a serious threat to public security throughout the world.
Due to heightened level of public security due to increased terrorist attacks, highly sensitive,
portable and miniaturized devices for explosives are of upmost importance. Nitroaromatic
compounds are widely used for military munitions especially as major component of explosive
materials. A number of approaches have been adopted to detect nitroaromatic compounds. These
approaches include electrochemical method, reverse-phase HPLC, chemiluminescence,
spectrophotometry, surface enhanced Raman scattering and immunosensing. One method that
offers a possible route for the development of sensing system is the use of functionalized
graphene based sensor.
In this research, graphene oxide and reduced graphene oxide and pristine graphene is
synthesized by Hummers‘ method, chemical reduction and liquid phase exfoliation of graphite
while tetraphenylporpyrin (TPP) is prepared by Adler-Longo‘s method and copper
tetraphenylporphyrin (Cu-TPP) by simple metallation. The graphene based nanomaterials are
functionalized with tetraphenylporphyrin and copper tetraphenylporphyrin PGr/TPP, PGr/Cu-
TPP, rGO/TPP, rGO/Cu-TPP hybrids are prepared to detect 1,3- dinitrobenzene (1,3-DNB) and
picric acid (PA) analytes. The GO, rGO, pristine graphene, DNB, TPP and CuTPP were
characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), IR and UV-Vis
spectroscopy. After functionalization, reduced graphene oxide based sensor shows high
sensitivity, reproducibility and selectivity for nitroaromatic compounds. Cyclic voltammetery
and electrochemical impedance spectroscopic techniques are used for the analysis of
electrochemical behavior of structures. rGO-Cu-TPP is found to exhibits the higher current
response, least charge transfer resistance and sensitivity of 1.50μA/μMcm2.towards 1,3-DNB and
rGO-TPP exhibits sensitivity of 1.007μA/μMcm2 towards picric acid. The improved sensitivity
of sensor can be attributed to the best adsorptive properties and rich electronic system of
tetraphenylporphyrin structure, large electronically active surface area and rapid charge transfer
of reduced graphene oxide.
