Ordered Pt₃Mn Intermetallic Nanoparticles Supported on Atomically Dispersed Mn-N-C as Electrocatalysts for Fuel Cells

Compared with conventional solid-solution alloy nanoparticles with disordered atomic structures, platinum (Pt)-based intermetallic compounds (IMCs) are recognized as highly promising electrocatalysts for practical fuel cell applications, on account of their long-range periodically ordered atomic arrangements. Nevertheless, the rational development of Pt-based catalysts featuring both high intrinsic activity and long-term durability remains a key challenge in this field. In this work, by simultaneously introducing manganese (Mn) with low-electronegativity into both the active component and the support, we report an efficient electrocatalyst toward the oxygen reduction reaction (ORR), composed of L1₂-ordered Pt₃Mn nanoparticles on Mn single-atom nitrogen-doped carbon support (L1₂-Pt₃Mn@Mn-N-C). The incorporation of Mn, the strong anchoring effect arising from the hierarchically porous structure of the support, and the directional interfacial electron transfer between L1₂-Pt₃Mn and Mn-N-C synergistically mitigate the adsorption strength of key oxygen intermediates and suppress the dissolution of surface Pt sites. Superior catalytic performance and durability are validated in proton exchange membrane fuel cells (PEMFCs), achieving a peak power density of 1.15 W cm^-2 under H₂/air conditions. After 30 000 square-wave cycles, the voltage loss at 0.8 A cm^-2 is only 19 mV, ranking it among the top-performing Pt-based cathode catalysts reported to date.