Medium-Sized Intermetallic PtCo Catalysts for Low-Pt Heavy-Duty Fuel Cells

Heavy-duty vehicles are becoming the primary focus of commercial deployment for proton exchange membrane fuel cells, yet their stringent operating conditions place far greater demands on fuel cell lifetime and efficiency. Meeting these requirements often necessitates elevated Pt loadings, as current cathode catalysts continue to face the challenge of balancing performance and durability under reduced Pt usage. Here, we present a catalyst design and synthesis strategy that overcomes this limitation by high-temperature pyrolysis of a bimetallic complex to yield a highly ordered L1₀ PtCo intermetallic nanocatalyst (∼80% ordering degree) composed of uniformly dispersed nanoparticles with an average size of ∼6 nm. These structural features enable the synergistic optimization of Gibbs-Thomson energy, Pt─Co bond enthalpy, and compressive strain, imparting the catalyst with outstanding structural and compositional stability while showing high activity. At a low cathode loading of 0.1 mg_Pt cm^-2, the resulting catalyst delivers a current density of 1.21 A cm^-2 at 0.7 V after 90 000 cycles of accelerated stress testing, corresponding to a Pt utilization of 6.8 kW g_Pt ^-1, more than two times higher than the U.S. Department of Energy target (2.5 kW g_Pt ^-1).