Core-Shell Fe@Pt Nanoparticles Supported on MOx/C As Enhanced Electrocatalysts for Cathode of PEMFC

Abstract

For fuel cell electric vehicle (FCEV), the amount of platinum electrocatalyst is required around 10 g per fuel cell stack of 80 kW, and non- or low-platinum electrocatalysts needed to reduce the amount of platinum per vehicle considering the production cost. Therefore, a large-scale synthesis method for low-platinum electrocatalyst is necessary for the commercialization of FCEV. Ultrasound-assisted polyol synthesis (UPS) is a one-pot method for the preparation of small and uniform size core-shell nanoparticles on the support and is suitable for mass production of platinum shell electrocatalyst in this respect. Platinum(Ⅱ) acetylacetonate, Iron(Ⅲ) acetylacetonate, and carbon support were dispersed in ethylene glycol, which is reducing agent, and irradiated with ultrasound for 3 h to reduce to the metal nanoparticles, followed by washing and drying to obtain a powder. The characterization was observed by analysis such as solution color visualization, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and electrocatalytic performance. Also, the synthesized samples were calcined at various temperatures to cause the atomic rearrangement to the most stable arrangement. The atomic accumulation of boundary between each atom and compression of platinum lattice that affects activity or durability of electrocatalyst has changed at specific temperature. And both synthesized samples with optimized synthesis condition for mass production and samples with the heat-treatment process show improved electrochemically active surface area (ECSA) and Oxygen reduction reaction (ORR) catalytic activity in the half-cell test and durable catalytic activity in the performance evaluation of membrane-electrode assembly (MEA) compared to existing Platinum catalyst. As renewable energy conversion and storage system is one of the main challenges, FCEV is developed to solve pollution from CO2 emission and oil depletion issues. Our low-platinum nanoparticle with uniform distribution synthesized in a sonochemical method could replace precious metal catalysts used in fuel cells.