• • Pt2CoNi intermetallic nanocatalyst delivers HER mass activity of 1.02 A/mg Pt with only 3.7 mV overpotential variation after 10,000 cycles, directly addressing the durability gap of conventional Pt/C (which typically degrades >20 mV under identical testing), enabling longer operational lifetimes in PEM water electrolyzers.
• • HOR kinetic mass activity reaches 4.08 A/mg Pt with 97.3% activity retention after 12 h at 0.1 V vs. RHE, surpassing commercial Pt/C by a factor of ~3–4 and meeting the U.S. DOE 2025 target of 0.44 A/mg Pt for fuel cell anodes, thus reducing Pt loading and system cost.
• • Superlattice ordering with alternating Pt and Co/Ni atomic layers creates surface microstrain that downshifts the d-band center, optimizing hydrogen binding energy toward thermoneutrality; this electronic modulation is the primary driver of the enhanced bifunctional activity and stability.
• • The synthesis protocol yields multiple Pt2CoNi grains with different orientations within single nanoparticles, generating microstrain without compromising structural integrity; this scalable strategy avoids the random elemental distribution and weak bonding inherent to disordered alloys, offering a viable path to industrial catalyst production.