PdNi Nanoframework and Nanochain Catalysts with Enhanced Oxygen Reduction Reaction Performance

Abstract The development of Pt‐free nanocatalysts with enhanced electrocatalytic activity and durability is essential for the commercialization of fuel cells. Herein, we report a new class of active and durable PdNi nanocatalysts for the oxygen reduction reaction (ORR) in an alkaline medium. PdNi nanoframework (PdNi‐NF), consisting of interconnected ultrathin ridges was synthesized through a galvanic replacement reduction (GRR) strategy using Ni nanoparticles, obtained by radiolytic reduction, as seeds. PdNi nanochain (PdNi‐NC), composed of aggregated nanoparticles, was produced by one‐pot γ‐radiation induced reduction. It was found that the carbon‐supported PdNi‐NF catalysts exhibit higher ORR activity and enhanced durability compared to PdNi‐NC/C (PdNi‐NC on carbon), Pd‐NP/C (Pd nanoparticle on carbon), and commercial Pt/C catalysts. The superior activity of PdNi‐NF/C catalyst may originate from the nanoframework morphology that facilitates the O 2 diffusion and the electronic effect induced by the sub‐surface PdNi alloy; the improved durability can be ascribed to the stable Pd‐enriched surface layer.