Confinement-Anchoring PtCoNi Nanoparticles in the Grooves of Sulfur-Doped Chiral Helical Carbon Nanotubes for Improved Oxygen Reduction Reaction

High-loading platinum-based carbon (Pt/C) materials (Pt > 40 wt %) are widely used to catalyze the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs). However, decreasing the Pt usage while maintaining the high activity and durability is required but is proven to be challenging. Herein, we report a synergistic strategy to anchor PtCoNi alloys in the grooves of sulfur (S)-doped chiral helical carbon nanotubes (HCNTs) for significantly improved ORR. Sodium thioglycolate (STG)-derived S-doping creates atomic-level Pt-trapping sites on the surface of groove-rich HCNTs. The obtained PtCoNi@HCNT-STG catalyst (Pt 6.93 wt %) achieves an ORR half-wave potential E 1/2 = 0.87 V versus reversible hydrogen electrode (RHE) in 0.10 M HClO 4 aqueous solutions, surpassing commercial Pt/C (Pt 20 wt %; 0.83 V versus RHE). Furthermore, PtCoNi@HCNT-STG exhibits a higher peak power density of 1.46 W cm–2 than commercial Pt/C (1.19 W cm–2) in membrane electrode assembly. After 30,000 accelerated durability test cycles, PtCoNi@HCNT-STG retained 80% of the initial current density, indicating its long-term durability and validating its potential applications for practical PEMFCs. This work is therefore significant to present a synergistic strategy to anchor and confine low Pt-loading alloys for efficient and durable ORR electrocatalysis.