Dual-Atom-Site-Rich Support Engineering Enables Strong Electronic Metal-Support Interaction for Superior PtZn Intermetallic Fuel Cell Catalyst

Rational carbon support engineering is a critical yet underexplored strategy for modulating the activity and durability of Pt-based oxygen reduction reaction (ORR) electrocatalysts in proton exchange membrane fuel cells (PEMFCs). Here, we show that dual-atom-site-rich carbon supports constitute an unique and highly promising architecture, playing a decisive role in electronic metal-support interactions (EMSI) and catalyst stability. Comparing single-atom-site-rich (M-NC, M = Co or Fe) and dual-atom-site-rich (CoFe-NC) supports for PtZn intermetallic nanoparticles (iNPs) reveals that conventional M-NC suffers from metal leaching, whereas cooperative CoFe-N 8 sites remain intact, enabling strong and persistent EMSI. Density functional theory (DFT) calculations reveal that the dual-atom-site configuration promotes electron donation to Pt, downshifts the Pt d -band center, reduces the kinetic barrier for the final * OH desorption step, and reinforcing nanoparticle anchoring, collectively enhancing ORR activity and stability. Consequently, PtZn@CoFe-NC catalyst achieves a mass activity of 1.93 A mg Pt −1 at 0.9 V vs. RHE in rotating disc electrode (RDE) tests. Membrane electrode assembly (MEA) delivers peak power density 2.18 W cm −2 (H 2 ─O 2 ), retaining ∼95% performance after 30k cycles accelerated stress test (AST). This work highlights that dual-atom-site-rich support engineering can serve as an effective approach to enhance performance of PtZn catalysts.