Development and analytical applications of composite electrodes with metal-metaloxide nanoparticle and carbon-based nanomaterial for use in energy conversion systems

Alternative energy sources are renewable, economical, environmentally friendly, and available in nature and continuously produced. Fuel cells are one of the environmentally friendly and clean energy sources, and studies on this subject have been given importance in recent years. It is known that composite electrodes modified with carbon material, metal and metal oxide nanoparticles have a catalytic effect on the electron transfer rate. This thesis work consists of three parts. In the first part, composite electrodes were prepared by electrochemical deposition of carbon-based materials, mixed-valent metal oxide (MeOx), metal oxide mixtures and metal nanoparticle on plain GCE. Electrochemical behavior of hydrazine oxidation was investigated by modifying MeOx on carbon-based materials such as GCE and CNT-NH2, CNT-COOH, C70, graphene oxide (GO). Modified electrode surfaces characterized by SEM-EDX, HRTEM, XRD, XPS and EIS. For the hydrazine oxidation peak current and potential, the modified surfaces with the best catalytic effect were determined. The use of these modified electrodes as anode material in fuel cells and their usability in sensor studies were investigated. In the second part, optimization studies were carried out by modifying the manganese oxide and vanadium oxide mixtures with Au nanoparticles on the ERGO surface. Simultaneous determination of hydrazine and nitrite on this electrode and real sample application were performed. The LOD value for hydrazine was found to be 0.15 µM, and the LOD value for nitrite was found to be 0.20 µM. In the third part, optimization studies were carried out by modifying the surface of ruthenium oxide and CNT-NH2 with Au nanoparticles. Simultaneous determination of hydrazine and nitrite and real sample application were made on this electrode. The LOD value for hydrazine was calculated as 10.30 µM, and the LOD value for nitrite was calculated as 9.70 µM. Sensitive determinations were also studied with amperometry.