An electrochemical synthesis strategy for composite based ZnO microspheres-Au nanoparticles on reduced graphene oxide for the sensitive detection of hydrazine in water samples

An electrochemical synthesis strategy has been developed to prepare a novel composite viz. reduced graphene oxide nanosheets/ZnO microspheres (∼0.6 μm)-Au nanoparticles (∼50 nm) modified glassy carbon electrode (GCE/RGO/ZnO-Au) for the trace level detection of hydrazine. Scanning Electron Microscopy (SEM) along with Energy Dispersive X-ray (EDX) analysis, confirming the presence of Au nanoparticles along with globular ZnO microspheres embedded over the entire surface of graphene nanosheets. The electrochemical detection of hydrazine is performed by cyclic voltammetry and chronoamperometry methods. Fascinatingly, the oxidation peak current of hydrazine at RGO/ZnO-Au modified GCE is 4.1 fold higher than that of RGO-Au modified GCE and 2.4 fold higher than ZnO/Au-modified GCE in addition to a favorable lower overpotential at 0.1 V. The chronoamperometric hydrazine sensor shows a very low detection limit of 18 nM with a high sensitivity of 5.54 μA μM^-1 cm^-2. The excellent analytical parameters of the RGO/ZnO-Au modified electrode over the various related modified electrodes suggest that the electrode can be advantageous for use in trace level detection of hydrazine in several industrial applications with low cost, ease of preparation, repeatability and long-term stability.