Eliminating dissolution of platinum-based electrocatalysts at the atomic scale

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Proton-exchange membrane fuel cells (PEMFCs) face durability challenges due to platinum (Pt) nanoscale material degradation at high voltages during oxygen reduction.
• Understanding Pt dissolution trends is critical for designing more robust fuel cell components.

Purpose of the Study:

• To provide atomic-scale insights into Pt dissolution on various surfaces.
• To develop and validate a new metric, intrinsic dissolution, for quantifying Pt loss.
• To engineer durable Pt-based nanomaterials for enhanced fuel cell performance.

Main Methods:

• Investigation of Pt dissolution on single-crystalline, thin-film, and nanoscale surfaces.
• Utilizing a gold (Au) underlayer to influence Pt surface structure and protect specific sites.
• Synthesis and testing of 3 nm Pt3Au/C nanoparticles.

Main Results:

• A gold (Au) underlayer promotes Pt(111) surface ordering and selectively protects low-coordinated Pt sites.
• The newly defined intrinsic dissolution metric correlates Pt loss with surface structure, size, and nanoparticle composition.
• 3 nm Pt3Au/C nanoparticles exhibited no Pt dissolution and a 30-fold durability improvement compared to 3 nm Pt/C up to 1.2 V.

Conclusions:

• Surface structure and the presence of a gold (Au) underlayer are critical factors in mitigating platinum (Pt) dissolution.
• The developed strategy of using a gold (Au) underlayer in Pt3Au/C nanoparticles significantly enhances durability for proton-exchange membrane fuel cell applications.