M.BAITOUL1,
H.AARABE1,
, M.MAAZA2 and M. Khenfouch1,2
1 Faculty of Sciences Dhar el Mahraz, Laboratory of Solid state Physics, Group of Polymers and nanomaterials, BP 1796 Atlas Fez 30 000 2 National research foundation, Ithemba Labs, Western Cape Province, South Africa
Abstract Graphene and nanostructured ZnO demonstrated rising optoelectronic properties especially for gas sensing applications. By the association of their properties, we have synthesized a ZnO nanorods in graphene solution. The non resonant Raman spectra of these nanostructures elucidate the interaction between ZnO and graphene. This work presents the ability of graphene-ZnO based nanorods to Hydrogen sensing.
Results and discussion
Introduction High interest to gas sensors, especially to hydrogen sensors, is explained by the growing interest to hydrogen as a future energy carrier [1]. Extensive investigations in the field of gas sensors are currently under way in order to obtain high-sensitivity, highselectivity, and small-size gas sensors consuming low energy. The synthesis of graphene-ZnO nanorods generate a promising nanocomposites for optoelectronic and optic applications with remarkable H2 sensing by the association of graphene’s low frequency-noise with the large surface-to-volume ratio of ZnO nanorods.
Setup We have synthesized graphene using hummer’s method. To synthesis ZnO nanorods an Equi-molar aqueous solution of 0.1 M of zinc nitrate (Zn(NO3)2) and hexamethylenetetramine (C6H12N4, HMT) was prepared using deionised water and mixed with graphene’s one. Si <100> substrates were then placed into the resultant mixture and heated at a constant temperature of 90°C in an oven for 24 hours.
The three principal steps to produce graphene powder using hummer’s method. Starting with graphite oxidation, after that the reduction with hydrazine hydrate of produced graphene oxide and finally a heat treatment to obtain graphene powder.
The grafting of ZnO on graphene is confirmed by the appearance of the peak at 1870 cm-1 attributed to CO vibration mode as show raman spectrum. Those defects are very important for many types of applications such as gas sensing.
The fast response in the reversible change in the resistivity with the exchange of charges between H2 and the graphene-ZnO surface proves the high sensitivity of this nanocomposite
Conclusion
Image Top-view with SEM of our synthesized ZnO nanorods.
To our knowledge, this work demonstrates, for the first time, the ability of graphene-ZnO based nanorods to Hydrogen sensing with remarkable high crystal structure. This work opens the way to combine graphene properties with other nanostructured materials to generate promising nanocomposites for optoelectronic applications.
Renferences [1] Aroutiounian, V. M., Metal oxide hydrogen, oxygen and carbon monoxide sensors (review paper), International Journal of Hydrogen Energy, 32 (2007), 1145-1158. [2] KHENFOUCH, M., et al., Synthesis and gas sensing properties of graphene-ZnO nanorods Global Journal of Physical Chemistry. Volume 2, Issue 2 (2011) pp. 165-169