Pt–Fe–Cu Ordered Intermetallics Encapsulated with N-Doped Carbon as High-Performance Catalysts for Oxygen Reduction Reaction

Abstract

Ternary platinum (Pt)-based ordered intermetallics represent a group of promising electrocatalysts in energy-conversion applications, because of their multielemental coupling that can potentially boost the activity and durability of the oxygen reduction reaction (ORR). Yet, the achievable catalysis performance is still susceptible to the inevitable transition metal leaching that can hardly be eliminated in an acidic environment. Herein, we report a nitrogen (N)-modified carbon (shell) encapsulated Pt–Fe–Cu ordered intermetallic nanoparticles (core) electrocatalyst for acidic ORR, where the Pt–Fe–Cu core presents a face-centered tetragonal (fct) phase. It is demonstrated that N-doped carbon shells can not only protect Pt–Fe–Cu cores from dissolution, agglomeration, coalescence, and Ostwald ripening but also enable the electronic structure regulation of the central Pt sites through the strong Fe–N coordination. The optimized Pt–Fe–Cu intermetallic with N-doped carbon shells delivers superior ORR activity and is more chemically stable over disordered Pt–Fe–Cu alloy, Pt–Fe–Cu intermetallics without a N-doped carbon shell, and commercial Pt/C, where the achievable ORR mass and specific activities are nearly 5-fold and 4-fold higher than those of commercial Pt/C in the acidic media, respectively.