Goblet-Like P-Driven Pt 3 Mn Alloys Enable High Power Density and 1000 h Durability in Practical Fuel Cells

Simultaneously achieving high power density and longevity in cost-effective proton-exchange membrane fuel cells (PEMFCs) is imperative for their commercialization, yet it poses a significant challenge to the fuel cell catalyst, particularly under light-duty vehicle (LDV) or heavy-duty vehicle (HDV) conditions. Here, we present a versatile phosphorus (P)-driven strategy to enhance the activity and durability of platinum–manganese (Pt 3 Mn) alloys, in which P acts as a pivotal bridging element between Pt 3 Mn nanoparticles and the carbon support as well as an activator for Pt 3 Mn surfaces. Importantly, goblet-like P -Pt 3 Mn enables outstanding peak power densities of 4.11 W cm –2 in H 2 /O 2 and 2.05 W cm –2 in H 2 /air under HDV condition, as verified by a third-party platform and stack-level validation. Meanwhile, P -Pt 3 Mn exhibits an exceptional accelerated stress test (AST) stability for 30 000 cycles (2.1% mass activity decline), significantly exceeding the U.S. Department of Energy (DOE) target. For commercial visibility, we demonstrate that the P -Pt 3 Mn-based fuel cell can be operated stably at a high current density of 3.0 A cm –2 beyond 1000 h. Detailed mechanistic and theoretical investigations reveal the excellent performance of P -Pt 3 Mn from the surface enrichment of P on Pt 3 Mn alloys and the formation of interfacial Pt–P–C coordination, which effectively promotes *OH desorption and mass transport as well as inhibits nanoparticle agglomeration. These groundbreaking results firmly establish P -Pt 3 Mn as the most efficient and durable fuel cell catalyst for practical PEMFC applications in urban transportation.