Dual Structure-Directing Agents for Superstructure Formation in PtCoCu Ternary Alloy Electrocatalysts

The development of high-performance Pt-based electrocatalysts with reduced metal loading is crucial for advancing proton exchange membrane fuel cell technology. Herein, we present a dual structure-directing agent approach for the precise formation of superstructures in uniform PtCoCu ternary alloy nanoparticles. Using zinc phthalocyanine for coordination-based composition control and dicyandiamide for carbon-mediated sintering suppression enabled molecular-level mixing and formation of an L10 face-centered cubic superstructure with exceptional uniformity and controlled electronic properties. The optimized L10-Pt45Co24Cu31 electrocatalyst exhibited remarkable oxygen reduction reaction activity with a mass activity of 2.13 A/mgPt at 0.9 V vs the reversible hydrogen electrode, representing a 7-fold improvement over commercial Pt/C and exceeding the DOE 2025 target by 483%. The electrocatalyst also demonstrated excellent durability, retaining more than 70% of its initial mass activity after 30 000 potential cycles. Comprehensive density functional theory calculations revealed that ternary alloying optimized the Pt and overall d-band centers, which were located at −2.87 and −2.50 eV, respectively, clarifying the electronic origin of the enhanced electrocatalytic performance. This dual structure-directing strategy overcomes the conventional trade-off between ordered phase formation and particle size control, demonstrating the potential of a tailored precursor design for developing next-generation electrocatalysts with precisely controlled superstructures.