Dense Platinum-Based Intermetallic Nanoparticles Confined into Hollow Mesoporous Carbon for Durable High-Power...

Heavy-duty vehicle (HDV) fuel cells require oxygen reduction reaction (ORR) catalysts with exceptional activity and durability under stringent operating conditions. However, conventional solid-solution Pt-based ORR catalysts often fail to simultaneously meet the requirements of high-power density and long-term stability, due to their inherent activity-stability trade-offs and mass-transport limitations at working conditions of fuel cells. Herein, we report a universal ligand-tuned co-reduction strategy to efficiently load Pt-based intermetallic compound (IMC) nanoparticles with high density (>50 wt% metal content and ∼3 nm particle size) and a high degree of ordering into hollow mesoporous carbon (HMC) by narrowing the reduction-potential gap between Pt and other transition metal precursors to achieve stable high-power HDV fuel cells. The dense and ordered IMCs ensure the efficient and stable ORR, while the mass-transport-favorable HMC promotes oxygen transport to the active sites. This design greatly enhances HDV fuel cell ORR activity, stability, and mass-transport efficiency. Under the HDV-relevant conditions (250 kPa_abs and cathode loading of 0.15 mg_Pt cm^-2), the optimized H-L1₀-PtCo/HMC catalyst achieves an exceptional current density of 1.73 A cm^-2 at 0.7 V and retains 85% after 90,000 accelerated durability cycles, significantly exceeding the U.S. Department of Energy targets. The findings establish H-L1₀-PtCo/HMC as a next-generation cathode electrocatalyst for HDV applications.