Investigation of the synthesis, characterization, and effect on cell performance of anode catalyst used in PEM fuel cells

In the search for sustainable solutions to the worldwide energy crisis, PEM fuel cells (PEMFCs) are attracting attention as an environmentally friendly energy production system. Within the scope of this thesis, an alternative microwave-assisted polyol method, which is not present in the literature and can operate under high pressure conditions, has been developed by modifying the polyol method for the synthesis of Pt/C, Ru/C and PtRu/C catalysts used in PEMFCs. This method allowed for catalyst synthesis at high temperatures and pressures, without being constrained by the boiling point of the mixture typically used in polyol synthesis. Additionally, catalysts were synthesized using conventional heating and microwave heating under atmospheric pressure to serve as references. For Pt/C catalysts, the effects of temperature (140–240 °C) and pH (12.0–13.0) were examined. For Ru/C catalysts, the temperature effect was investigated in the range of 160–240 °C, and based on the findings, PtRu/C catalysts were synthesized at 200 °C and 240 °C. By optimizing pH and temperature during the synthesis process, the sizes of the synthesized Pt nanoparticles were effectively controlled, achieving Pt, Ru, and PtRu nanoparticles smaller than 1.5 nm without the use of external stabilizing chemicals and successfully depositing them onto carbon supports. Characterization studies were carried out using TGA, FTIR, XRD, SEM-EDS, TEM, BET, CV, and LSV methods. For the activity tests, MEAs were prepared with the catalysts synthesized in this study on the anode side, commercial catalysts on the cathode side, and a Nafion membrane. The activities were determined in a single-cell system using experimental designs based on the Taguchi method. The effects of hydrogen and air feed rates, as well as cell temperature, were examined at three different levels, and the activities of commercial and synthesized catalysts were compared. Catalysts synthesized at high temperatures demonstrated activities comparable to commercial Pt/C (223 mW/cm² @ 70 °C), while the Pt/C-160 catalyst exhibited 19% higher anode activity (266 mW/cm²).