Synthesis and characterization of Pt-Co/C binary and Pt-Co-Ni/C ternary core-shell structured nanoparticle electrocatalysts for polymer electrolyte membrane fuel cells

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Due to its high power density, high energy conversion efficiency and zero emission, polymer electrolyte membrane (PEM) fuel cell has been widely considered to be the future power devices for many different types of applications. As a result, extensive efforts have been made in the development of PEM fuel cell technology. Nevertheless, PEM fuel cells continue to face cost and durability challenges that are predominately determined by the fuel cell materials and components. Paramount among them is the cathode electrocatalyst that catalyzes the oxygen reduction reaction (ORR). Platinum (Pt) supported on carbon has been commonly used in the PEM fuel cells as the cathode electrocatalyst. However, the high cost of Pt makes the cathode electrocatalyst the most significant factor that is responsible for the high cost of fuel cells. Development of more efficient ORR catalysts to reduce the dosage of Pt or replace the expensive Pt has been the focus of many fuel cell researchers. In recent years, Pt-based alloys have been reported to have intrinsic enhancement of the electrocatalytic activity of Pt catalysts for ORR, which can potentially reduce the Pt dosage and improve the fuel cell performance. However, there is a poisoning effect of the non-precious metals dissolved from the Pt alloy under the harsh fuel cell operation environment, and this effect has been reported to cause durability issues. This effect has been reported to cause durability issues. In this work, we propose to use three approaches to synthesize core-shell structured nanoparticle electrocatalysts for applications in PEM fuel cells. The core-shell structured catalysts have a non-precious metal/metal alloy core and a Pt skin. This core-shell structured catalyst will significantly improve the utilization of Pt, enhance the intrinsic activity of Pt due to more favorable lateral strain which effectively prevents the leach-out of the non-precious metal. We plan first to systematically investigate the synthesis procedures of binary and ternary core-shell structured catalysts using various synthesis methods with the goal of developing a reliable and cost-effective process and then study the scale-up effect with an optimized synthesis route to at least 20 g/batch level. The proposed work is expected to lead to a practical industrial synthesis process to produce highly active core-shell structured catalysts for PEM fuel cells at a significantly low cost.