Development of cobalt oxide modified electrodes and their investigation in electrocatalytic applications

Present thesis concerns with electrochemical preparation of cobalt oxide and platinum nanoparticle composite electrodes on a GCE surface in the pursue of its catalytic applications. Electrochemical deposition of the metal-metal oxide film structure has been carried out by pulsed deposition and cyclic voltammetry. The parameters affecting the deposition conditions have been evaluated by monitoring oxygen reduction reaction in pH 5.0 acetate buffer. Solution parameters such as medium pH, buffer type and Co(II) concentration have been optimized along with the operational parameters such as scan rate and pulse duration. In case of cyclic voltammetry, the repetitive cycle number has been optimized. Under optimal conditions, the electrodes developed by both electrochemical modes have been compared with bare and Pt nanoparticle and CoOx modified electrodes. In both methods, the Pt/CoOx/GCE has given the best result in terms of peak current and peak potential. In the final part of the thesis, Pt/CoOx/GCE was used as a platform for a biosensor. Plant tissues can be used as an economic alternative to purified enzymes and bayberry fruit which is known to contain polyphenol oxidase and peroxidase enzymes was used for this purpose. Homogenate samples have been immobilized onto the electrode surface and used for phenol detection. In addition the electrode was also used as a platform for tyrosinase enzyme based biosensor and very promising results have been obtained.