Green synthesis of graphene quantum dot-and its electrochemical, antioxidant and antimicrobial activities
Turunç, Ersan | Döğen, Aylin | Binzet, Rıza
The present work reports the synthesis of graphene quantum dots with a green approach. Graphene quantum dots (ssGQDs) were synthesized via Sarcopoterium spinosum (L.) Spach. fruit powder extract. The prepared ssGQDs were characterized by UV-Vis Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and Malvern Zeta Sizer. The electrochemical activity of ssGQDs was investigated by cyclic voltammetry (CV) and differential puls voltammetry (DPV) methods. The synthesized ssGQDs were used to prepare electrosensor and tested for the electrochemical determination of dopamine. DPV studies showed a low detection limit of 0.107 μM over a wide linear concentration range of 10–800 μM. Antibacterial and a...
Green Synthesis of Reduced Graphene Oxide Decorated with Silver Nanoparticles Using Onosma bracteosa Leaf Extract for Efficient Electrochemical Detection of Hydrogen Peroxide
Turunç, Ersan | Binzet, Rıza
In this study, a simple, cost-effective and eco-friendly method was performed for the production of silver nanoparticle decorated reduced graphene oxide (rGO-Ag) nanocomposite using Onosma bracteosa leaf extract as reducing and stabilizing agent. The structure of the synthesized rGO-Ag nanocomposite was characterized by UV–Vis, XRD, SEM, TEM, EDX, and XPS. The synthesized rGO-Ag nanocomposite was used to fabricate an electrochemical sensor (rGO-Ag@GCE) for the determination of hydrogen peroxide. Electrochemical reduction of hydrogen peroxide was performed using DPV on rGOAg@GCE in 0.1 M PBS. The rGO-Ag@GCE exhibited good response in the linear concentration range of 25 µM to 800 µM, with a LOD of 0.11 µM. Amperometric measurements showed that the prepared sensor did not have a significant ...
Enhanced electrochemical sensing of nitrite ions in water samples using hydroxyapatite-zinc oxide nanocomposite modified carbon paste electrode
Turunç, Ersan | Binzet, Rıza
This study reports the green synthesis of a hydroxyapatite‑zinc oxide (HAp-ZnO) nanocomposite using Onosma mersinana leaf extract (OMLE) and its application as a highly sensitive electrochemical sensor for nitrite ion detection. The structural and surface characteristics of the synthesized nanomaterial were confirmed by XRD, which revealed crystalline phases corresponding to both HAp and ZnO; SEM analysis showed uniform morphology; EDX confirmed elemental composition; and XPS identified chemical states of Zn, O, Ca, C, and P, verifying successful ZnO doping. The HAp-ZnO nanocomposite was incorporated into a carbon paste electrode (CPE) to fabricate the CPE@HAp-ZnO100 sensor for the electrochemical detection of nitrite. The electrochemical behavior of nitrite on the CPE@HAp-ZnO100 electrode...