Achieving Highly Durable Random Alloy Nanocatalysts through Intermetallic Cores

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Platinum (Pt) catalysts are crucial for the oxygen reduction reaction (ORR) but are expensive and prone to deactivation.
• Bimetallic alloys offer a strategy to improve ORR performance and reduce costs, yet durability remains a challenge due to metal leaching.

Purpose of the Study:

• To investigate the effect of intermetallic versus random alloyed cores on the durability of PtCu core@shell nanocatalysts for the ORR.
• To understand the mechanisms behind enhanced catalyst stability.

Main Methods:

• Fabrication of PdCu@PtCu core@shell nanocatalysts with either random alloy (FCC A1) or intermetallic (CsCl-like B2) PdCu cores.
• Electrocatalytic activity and durability testing under ORR conditions.
• Classical molecular dynamics simulations to probe leaching mechanisms.

Main Results:

• The nanocatalyst with an intermetallic PdCu core exhibited superior durability, with only an 18% decrease in activity and minimal copper leaching after stability testing.
• The nanocatalyst with a random alloy PdCu core showed significantly lower durability, with a 58% decrease in activity and greater copper leaching.
• Molecular dynamics simulations supported the experimental findings, explaining the enhanced stability of intermetallic-supported catalysts.

Conclusions:

• Intermetallic cores provide a robust platform for stabilizing alloyed shells, leading to significantly enhanced electrocatalytic durability.
• This core@shell design strategy, particularly utilizing intermetallic seeds, is a promising approach for developing durable and cost-effective catalysts for the oxygen reduction reaction and potentially other applications.