High-performance transition metal-doped Pt3Ni octahedra for oxygen reduction reaction

Bimetallic platinum-nickel (Pt-Ni) nanostructures represent an emerging class of electrocatalysts for oxygen reduction reaction (ORR) in fuel cells, but practical applications have been limited by catalytic activity and durability. We surface-doped Pt3Ni octahedra supported on carbon with transition metals, termed M-Pt3Ni/C, where M is vanadium, chromium, manganese, iron, cobalt, molybdenum (Mo), tungsten, or rhenium. The Mo-Pt3Ni/C showed the best ORR performance, with a specific activity of 10.3 mAčm2 and mass activity of 6.98 A—gPt, which are 81- and 73-fold enhancements compared with the commercial Pt/C catalyst (0.127 mAčm2 and 0.096 A/mgPt). Theoretical calculations suggest that Mo prefers subsurface positions near the particle edges in vacuum and surface vertexédge sites in oxidizing conditions, where it enhances both the performance and the stability of the Pt3Ni catalyst.