Title : An electrochemical sensor based on graphene nanosheets-zinc oxide composite coated glassy carbon electrode for the sensitive determination of para-nitrophenol
Graphene and graphene oxide carbon materials have attracted a great deal of attention for sensing applications due to their excellent charge transfer mobility, large specific surface area and good electrocatalytic activity1,2. Recently, one new perspective is to utilize ideal single-atom-thick GN as a support to anchor functional nanomaterials to form new nanocomposite with potential application2,3. On the other hand, there is no report in the literature for the electrochemical determination of para-nitrophenol (p-NP) using graphene nanosheets-zinc oxide nanoparticles (GNS/ZnONPs) based composite as sensing material. In the present study, ZnONPs have been synthesized by wet chemical method and have been dispersed with graphene oxide (GO) for the fabrication of GNS/ZnONPs composite using glucose as reducing agent. Reduction of GO to GNS and anchoring of ZnONPs on GNS have been simultaneously achieved. The materials were characterized using X-ray diffraction, scanning and transmission electron microscopy, Raman and energy dispersive X-ray spectroscopy. Electrode characterizations were carried out using electrochemical impedance spectroscopy, chronocoulometry and cyclic voltammetry (CV). The GNS/ZnO nanocomposite was used as a modifier for glassy carbon electrode (GCE) by depositing the composite onto GCE using drop deposition method. The modified electrode has been applied for the determination of (p-NP) using voltammetric techniques. The good dispersion of ZnO nanoparticles with GNS showed enhanced electrocatalytic activity towards the electrode reduction of (p-NP) compared with individual GNS modified GCE in 0.1M phosphate buffer (pH 6.8) using CV. A wide linear working range of 9.90 x10-8 M to 2.18 x10-6 M and detection limit of 8.8 x 10-9 M using square wave adsorptive stripping voltammetry was obtained. Both ortho and para-nitrophenols can be detected simultaneously at the developed electrode in presence of meta-nitrophenol without the interference. The proposed method was applied to determine p-NP in river and ground water samples with satisfactory recoveries.
Audience take away:
• The audience will be able to learn new advances in Electrochemical Sciences for the sensitive determination of some environmentally hazardous substances.
• This will help the researchers and scientists to learn new ideas about the Electrochemical technology and its applications in various fields like Electrochemical sensors/biosensors and supercapacitors.