Plant based synthesis of silver doped reduced graphene oxide and utilization for the electrochemical determination of hydrogen peroxide

In this thesis, silver doped reduced graphene oxide silver (iGO-Ag) nanocomposite was synthesized via plant extract of Onosma bracteosa Hausskn & Bornm. The characterization of the nanocomposite was performed by UV-Vis spectroscopy, X-ray Diffraction Diffractometry (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Transmissive Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and Dynamic Light Scattering (DLS). UV-Vis spectroscopy results showed that the iGO-Ag nanocomposite was obtained by simultaneous reduction of graphene oxide (GO) and silver ions. In SEM and TEM analyzes, it was observed that silver nanoparticles were homogeneously dispersed on the reduced graphene oxide (iGO) surface. As a result of DLS studies, the average particle size and zeta potential of the iGO-Ag nanocomposite structure were determined as 74.48 nm and -21.4 mV, respectively. The synthesized iGO@Ag nanocomposite was used to prepare a sensor for the electrochemical determination of hydrogen peroxide (H2O2). The synthesized iGO@Ag nanocomposite was evaluated a platform to improve a sensor for the electrochemical determination of hydrogen peroxide (H2O2). For this end, glassy carbon electrode (GCE) was modified with iGO@Ag nanocomposite structure (iGO-Ag@GCE) and modified electrode was used for the electrochemical determination of H2O2. The proposed electrosensor showed a linear trend in the concentration range of 25 µM to 800 µM. From the linear equation, the detection limit (LOD) was calculated to be 0.11 µM. The selectivity and sensitivity of the developed sensor were tested against interference species such as glucose, ascorbic acid, dopamine and uric acid. Amperometric measurements showed that the prepared sensor did not have a significant response to the interference species.