Au-Doped Stable L1₀ Structured Platinum Cobalt Ordered Intermetallic Nanoparticle Catalysts for Enhanced Electrocatalysis

Bimetallic Pt₃Co alloys are the commercial electrocatalysts for the oxygen reduction reaction in a fuel cell, but their high Pt loading and durability are a concern. Working toward the goal of reducing the amount of Pt and simultaneously increasing the activity and stability of the catalyst, we describe two new structures of ordered intermetallics consisting of Pt₄Co₅ nanocatalyst protected by Au atoms. Varying the temperature for the formation of the intermetallics, two distinct PtCo structural characteristics were observed in the nanoparticles: one with a simple intermetallic structure and the other with an intermetallic structure core protected by a shell of Pt atoms. The improved electrocatalytic activity and durability are attributed to the atomically ordered structure of PtCo nanoparticles along with protective surface Au atoms as confirmed by density functional theory (DFT) calculations and experimental results.