Green synthesis of coo nanoparticles from pomegranate peel extract, use as a catalyst support material and investigation of the effectiveness of this support material in pem fuel cell application

In this thesis, cobalt oxide (CoO) nanoparticles were successfully synthesized as a support material for ruthenium (Ru) metal, which has high catalytic activity in the hydrolysis reaction of sodium boron hydride (NaBH4). CoO nanoparticles were produced using a green synthesis approach, an environmentally friendly and sustainable method, using pomegranate peel extract. This method minimized toxic chemicals and provided environmental sensitivity and an innovative synthesis strategy by utilizing natural resources. The physical and chemical properties of the CoO nanoparticle-supported Ru catalyst were analyzed in detail using advanced characterization techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Raman spectroscopy. These characterization studies confirmed the catalyst's homogeneous distribution, high-purity synthesis, and structural stability. In particular, SEM analyses revealed that the size of CoO nanoparticles was on the nanometer scale and thus had a large surface area. The effects of different parameters were studied in detail in the catalytic performance tests in the NaBH4 hydrolysis reaction. These parameters include NaOH concentration, NaBH4 concentration, catalyst amount, and reaction temperature. As a result of the studies, it was determined that the CoO nanoparticle-supported Ru catalyst exhibited its optimum performance at 2,5% NaOH concentration. In addition, an increased reaction rate was observed with increasing NaBH4 concentration. It was also found that increasing the amount of catalyst and temperature positively affected the reaction kinetics. These results showed that the catalyst exhibited a compelling performance in NaBH4 hydrolysis and provided a detailed understanding of the kinetic parameters of this reaction. Furthermore, platinum (Pt) doping of CoO nanoparticle-supported Ru catalyst was investigated for its potential use in proton exchange membrane (PEM) fuel cells. This study demonstrated that Pt-doped CoO-supported Ru catalyst exhibited high activity in PEM fuel cells. Pt doping was found to improve the electrochemical stability of the catalyst and contribute significantly to the fuel cell performance.