High performance layer-by-layer Pt₃Ni(Pt-skin)-modified Pd/C for the oxygen reduction reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Bimetallic catalysts are crucial for fuel cell electrocatalysis.
• Oxygen reduction reaction (ORR) efficiency is key for fuel cell performance.
• Developing durable and highly active electrocatalysts remains a challenge.

Purpose of the Study:

• To synthesize and characterize a novel Pt-Ni core-shell catalyst with a Pt-skin structure.
• To evaluate the electrocatalytic activity and durability of the Pt3Ni(Pt-skin)/Pd/C catalyst for ORR.
• To investigate the role of the Pt-skin structure in enhancing catalyst performance and stability.

Main Methods:

• Synthesis of a Pd/C core catalyst.
• Modification with Ni underpotential deposition (UPD).
• Pt atomic layer-by-layer growth via galvanic replacement using Zn UPD.

Main Results:

• The Pt3Ni(Pt-skin)/Pd/C catalyst exhibited superior ORR performance.
• Achieved a Pt specific activity of 16.7 mA cm⁻² and mass activity of 14.2 A mgPt⁻¹.
• Demonstrated significantly enhanced durability in accelerated testing, inhibiting Ni leaching.

Conclusions:

• The Pt-skin configuration on Pt3Ni/Pd/C is highly effective for ORR.
• This catalyst design offers a substantial improvement over commercial Pt/C catalysts.
• The developed catalyst shows promise for long-term fuel cell applications due to its stability.