Dynamic Surface Dealloying for Pt₃Co/C Catalysts with a Pt-Enriched Surface for the Oxygen Reduction Reaction

Pt-based alloys are important catalysts in fuel cells, especially for the oxygen reduction reaction (ORR). A key problem to be addressed is to develop high-activity ORR catalysts with low Pt loading or, equivalently, to increase the catalytic activity per Pt amount. Here, we report a Pt–Co alloy catalyst with Pt-enriched skin and a Pt–Co core structure via microwave activation and ethylene glycol reduction. The synthesis route is efficient and controllable, resulting in highly active catalysts with a fine particle size and narrow size distribution. The synthesized catalysts show significant advantages in ORR activity compared to commercial catalysts. We proposed that the improved activity and stability are due to a Pt-enriched surface of the Pt3Co catalysts, and such a surface structure is dynamically formed via selective etching of Co during nonequilibrium synthesis under the harsh environment of acid, ethylene glycol reduction, and microwave treatment.