Cobalt-Doped Pd@Pt Core–Shell Nanoparticles: A Correlative Study of Electronic Structure and Catalytic Activity in ORR

Platinum (Pt) is a critical catalytic component used in polymer electrolyte membrane fuel cells. However, its low abundance, limited supply, and increasing demand have limited the commercial applications of this metal. One of the most recent ways to meet these demands is to utilize Pt-based bimetallic nanoparticles. Using the Pt metal as the shell material of the catalyst not only increases the surface area but also creates an interfacial interaction between the core metal and platinum, which results in enhanced catalytic activity. Recently, octahedral Pd@Pt nanoparticles with controllable Pt shells have been shown to exhibit greatly enhanced activity and durability compared to commercial Pt/C. In this study, Pd@Pt nanoparticles will be surface doped with cobalt to further boost their durability and activity. Characterizing the synthesized catalyst with X-ray absorption fine structure at the Pt L3-edge and cobalt K-edges, together with performance tests, has revealed information about the effect of the dopants on the catalytic activity of catalysts. The results of the local and electronic structures of the catalysts are correlated with electrocatalytic activity to optimize performance. Cobalt has been found to be simultaneously efficient in enhancing catalytic activity, increasing long-term durability, and reducing the platinum content in the catalysts.