High-performance core-shell Pt3Cu@Pt/C nanocatalysts for oxygen reduction reaction

Developing efficient and durable oxygen reduction reaction (ORR) catalysts is critical for advancing proton exchange membrane fuel cells (PEMFCs). While Pt-based alloy catalysts exhibit enhanced ORR activity, their disordered nanostructures often compromise durability. In this work, a carbon-supported Pt 3 Cu alloy catalyst with a core-shell architecture (Pt 3 Cu@Pt/C) was synthesized via a controlled impregnation-reduction method followed by acid-washing to construct a Pt-rich shell. Comprehensive physicochemical characterizations confirmed the formation of a face-centered cubic (FCC) structure with a Pt 3 Cu core and a Pt-rich shell. Alloying with Cu was found to downshift the Pt d-band center, thereby optimizing the adsorption strength of oxygen intermediates. Electrochemical evaluations revealed that the Pt 3 Cu@Pt/C catalyst exhibited a mass activity (MA) of 0.37 A mg −1 and an electrochemical surface area (ECSA) of 89.43 m 2  g −1 , surpassing commercial Pt/C. Although the core-shell treatment slightly reduced ORR activity compared to untreated Pt 3 Cu/C, the Pt 3 Cu@Pt/C catalyst demonstrated exceptional durability, retaining >70% of its initial ECSA and showing only a 27% decay in MA after 30,000 accelerated stress test cycles, far outperforming both Pt 3 Cu/C and commercial Pt/C. Density functional theory (DFT) calculations revealed that the Pt shell increased Cu vacancy formation energy by 0.8 eV, effectively suppressing Cu dissolution and enhancing structural stability. This work highlights the synergistic electronic and geometric effects of core-shell nanostructures in balancing ORR activity and durability, providing insights for designing advanced Pt-based catalysts.