Hierarchical low Pt-loading “core-shell” electrocatalysts for the oxygen reduction reaction in fuel cells

The sluggish kinetics of the oxygen reduction reaction (ORR) hinder cost-effective polymer electrolyte fuel cells (PEFCs), which rely on scarce, expensive platinum-based electrocatalysts (ECs). Here, we present a novel synthesis method for ORR ECs achieving exceptional platinum utilization. The design features a hierarchical “ multi-carbon ” support comprising carbon nanoparticles interacting with graphene nanoplatelets as the “ core ”, encapsulated by a porous carbon nitride (CN) “ shell ”. This configuration promotes strong core/shell interactions and a bimodal active site distribution, consisting of chemically dispersed Pt and Ni single-atom complexes and PtNi x alloy nanoclusters embedded in the CN shell. These advantages enable high activity and durability, achieving an ORR activity of 1.6 A mg Pt −1 at 0.9 V vs . RHE-an order of magnitude higher than Pt/C (0.17 A mg Pt −1 ). A proof-of-concept PEFC demonstrates a specific power of 12.0 kW g Pt −1 at 0.60 V. This approach offers a significant step toward more efficient and sustainable PEFC technologies.