Designed synthesis of well-defined Pd@Pt core-shell nanoparticles with controlled shell thickness as efficient oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Polymer electrolyte membrane fuel cells (PEMFCs) require efficient and durable catalysts for the oxygen reduction reaction (ORR).
• Reducing the high cost associated with platinum (Pt)-based catalysts is crucial for widespread PEMFC adoption.
• Developing low-Pt content catalysts with improved performance remains a significant challenge.

Purpose of the Study:

• To synthesize well-defined palladium-platinum (Pd@Pt) core-shell nanoparticles (NPs) with controlled platinum shell thickness.
• To investigate the effect of Pt shell thickness on the electrocatalytic activity and durability for ORR.
• To evaluate the potential of these novel NPs as low-cost, high-efficiency catalysts for PEMFCs.

Main Methods:

• Facile wet chemical synthesis of Pd@Pt core-shell NPs via in situ heteroepitaxial growth of Pt on Pd NPs.
• Precise control over Pt shell thickness (0.4–1.2 nm) by adjusting the Pt:Pd molar ratio.
• Electrocatalytic performance evaluation for ORR and durability testing in a membrane electrode assembly.

Main Results:

• Pd@Pt NPs with a Pt shell thickness of 0.94 nm demonstrated superior specific activity and durability compared to other shell thicknesses and commercial Pt/C catalysts.
• The synthesis method allowed for simplified production of NPs with well-defined sizes and shell thicknesses.
• Single-cell performance of Pd@Pt NPs with 0.94 nm shells was comparable to commercial Pt/C, despite lower Pt content.

Conclusions:

• Optimized Pt shell thickness in Pd@Pt core-shell NPs is critical for enhancing ORR electrocatalytic performance.
• These Pd@Pt NPs offer a promising pathway towards low-cost and high-efficiency PEMFC applications.
• The facile synthesis method facilitates the scalable production of advanced fuel cell catalysts.