Synergistic Pt single-atom and Pt nanoparticle catalysts anchored on N-doped mesoporous carbon architecture boosting high-performance oxygen reduction in PEMFCs

Abstract

Platinum-based catalysts are indispensable for the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs), yet simultaneously achieving high activity, durability, and metal utilization remains a critical challenge. Herein, we report a heterostructured electrocatalyst (PtSA-NP/MPC950) that integrates atomically dispersed Pt single atoms(SA) with nanoparticles(NP) on a nitrogen-doped mesoporous carbon. A Zn-assisted strategy was employed to pre-construct well-defined coordination sites: Zn volatilization generated stable Pt–N₃ moieties,which anchor Pt single atoms and direct the controlled nucleation of nanoparticles. This unique architecture exhibits a half-wave potential of 0.90 V vs. RHE in acidic media, a mass activity of 1.26 A mgPt⁻¹ (6.3-fold higher than that of Pt/C), and a 42 % improvement in durability after 50,000 cycles. The hierarchical porous carbon host provides efficient mass transport, while the synergistic interaction between Pt single atoms and nanoparticles optimizes intermediate binding—thereby accelerating ORR kinetics and suppressing catalyst degradation. Complementary DFT calculations further reveal that the cooperation between SA and NP lowers the energy barrier of the rate-determining step and inhibits H₂O₂ formation, establishing a direct structure–property relationship. This study not only uncovers the synergistic mechanism of Pt single atoms and nanoparticles for the first time but also introduces a generalizable Zn-assisted strategy for constructing high-loading, durable and efficient ORR catalysts for PEMFCs.