Oxygen reduction reaction activity and durability of Pt-Ta-Co ternary catalysts for polymer electrolyte fuel cells

Enhancing the oxygen reduction reaction (ORR) activity and durability of cathode electrocatalysts in polymer electrolyte fuel cells (PEFCs) will be crucial for the implementation of fuel cell electric vehicles (FCEVs). Here, ternary Pt-Ta-Co catalysts are developed, in which platinum, tantalum, and cobalt components are co-decorated onto a carbon support. During synthesis, the tantalum-containing electrocatalysts phase-separate into Pt-Co alloy nanoparticles and TaO x phases, forming a nanocomposite structure. The presence of tantalum oxide suppresses Pt-Co particle growth during high-temperature synthesis (leading to high initial activity) and during load cycling (suppressing Pt-Co agglomeration and ripening). Furthermore, the presence of TaO x phases prevents direct contact between the catalyst nanoparticles and the carbon support, preventing carbon corrosion during start-stop cycling. Overall, Pt-Ta-Co catalysts presented outperform conventional Pt/carbon catalysts in terms of both initial activity and durability. This work paves the way for the design of next-generation PEFCs for FCEVs. • Pt-Co/TaO x catalysts synthesized by co-decoration on carbon followed by heating. • Improved initial cell performance compared with conventional Pt/carbon catalysts. • Load cycle durability improved via suppression of agglomeration/ripening. • Start-stop cycle durability improved by separating Pt-Co from carbon support.