Atomically Dispersed Pt‐N _x and Ce‐N _x Dual Sites Enhance PtCe Nanoparticles for Oxygen Reduction Reaction

Abstract Developing stable and high‐performance Pt‐based alloy catalysts is essential for advancing the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), as the harsh operating conditions often cause the leaching of transition metals. Herein, a highly stable electrocatalyst (Pt‐Ce‐N‐C) consisting of ultra‐small Pt‐Ce alloy nanoparticles and atomically dispersed Pt‐N _x and Ce‐N _x dual sites for highly efficient ORR is reported. The Pt‐Ce‐N‐C demonstrates a remarkable mass activity (MA) of 1.17 A mg _Pt ⁻¹ , 7 times higher than that of commercial Pt/C. Importantly, the performance attenuation is negligible even after 30 000 cycles in accelerated durability tests (ADT). In H ₂ /Air PEMFC testing, the Pt‐Ce‐N‐C exhibits exceptional performance and durability with a peak power density of 1.229 W cm ⁻² ‐twofold of Pt/C‐ and retaining 87.9% of its performance (1.08 W cm ⁻² ) after 30 000 ADT cycles. Combined theoretical and experimental results reveal that Ce‐N _x sites primarily function as an adsorption site for reactants due to their strong affinity for oxygen, while PtCe alloy and Pt‐N _x serve as active centers for ORR. This synergistic interaction between the alloy and dual‐site design significantly enhances catalytic activity and durability.