Graphitized Carbon Veils Break the Activity-Durability Trade-Off in PEMFC Cathode Catalysts

Abstract

Proton exchange membrane fuel cells (PEMFCs) require cathode catalysts that combine high Pt utilization, efficient mass transport and long-term durability under demanding practical operation. However, recent developed Pt-based catalysts with small particle sizes suffer from a persistent activity-durability trade-off because highly accessible Pt surfaces are vulnerable to oxidation and dissolution. Here, we present a scalable Co-tannic acid (TA) coordination strategy that directly upgrades commercial Pt/C into graphitized carbon veil (GCV) Pt3Co by thermally converting a complex into a Pt-Co surface alloy and thin GCV while modifying the carbon surface. This integrated structure improves oxygen reduction activity, lowers local oxygen transport resistance and facilitates water removal while preserving reactant accessibility. Under heavy-duty operation, GCV-Pt3Co achieves a peak efficiency of 72%, high rated power density (1.21 W/cm 2 @0.67V). Also, GCV-Pt3Co exhibits outstanding durability under long-term operation. After accelerated durability test (ADT) cycles, it retains a Pt utilization of 3.95 kW/gPt and markedly extends the ADT projected lifetime to 27,800 h. This work establishes polyphenol-metal coordination as a practical route for upgrading parent catalyst into active and durable PEMFC catalysts.