Microwave synthesis of reduced graphene oxide decorated with silver nanoparticles for electrochemical determination of 4-nitrophenol

A facile microwave-assisted synthesis of a reduced graphene oxide-silver (rGO-Ag) nanocomposite and its application towards the electrochemical determination of 4-nitrophenol (4-NP) are reported. The nanocomposite was characterized using UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman, and X-ray photoelectron spectroscopy (XPS). The formation of spherical AgNPs was confirmed from the single surface plasmon absorption feature and the TEM analysis. The reduction of GO was conveniently monitored using D and G band intensity ratio (I-D/I-G) of Raman spectrum and XPS analysis. A glassy carbon electrode (GCE) was modified with the rGO-Ag nano composite and used for the electrocatalytic reduction and determination of 4-NP The nanocomposite modified electrode displayed a higher reversible redox peak currents and lower charge transfer resistance (R-ct) towards [Fe(CN)(6)](3-/4-) couple compared other controlled electrodes. The amperometric i-t curve response to 4-NP at a working potential of -0.52 V (vs. Ag/AgCl) covers the 1-1100 mu M concentration range, and the limit of detection is 0.32 mu M. The sensor is selective for 4-NP even in the presence of 50-fold higher concentrations of analogues such as bromophenol blue, 2-amino-4-nitrophenol, 2-chlorophenol and 2,4-dinitrophenol. The nanocomposite modified GCE was successfully applied for the determination of 4-NP in spiked real water samples where it gave recoveries between 94.3% and 100.2% at a concentration level of 10-50 mu M. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.