Structure Design Reveals the Role of Au for ORR Catalytic Performance Optimization in PtCo‐Based Catalysts

Au-incorporation is a promising strategy to retard composition-loss in Pt-based catalyst. However, the unclear mechanism limits guided catalyst design and the performance optimization. Here, direct evidence is provided to validate the outward diffusion of Au atoms in Au-core/Pt-based-shell structures. A Co interlayer is built between the Au-core and PtCo-based shell to exclude the possibility of atomic diffusion caused by interfacial alloying. In conjunction with the improved catalytic durability of the Au-core@Pt-based-shell structure, it is reasonable to conclude that it is the subsurface segregated Au atoms rather than interfacial interaction that boosts the catalytic durability of Au-core/Pt-based-shell structured catalysts towards oxygen reduction reaction. More importantly, by constructing Au-core@Co-interlayer@PtCoAu-shell multilayer structure, the specific (1.730 mA cm(-2)) and mass (0.692 A mg(Pt)(-1)) activities are enhanced 7- and 4- fold relative to the commercial Pt/C. After 10 000 cycles of accelerated durability test, the mass activity loss for the multilayered catalyst is as low as 6.14% while the loss exceeds 35% for the commercial Pt/C catalyst. The improved catalytic performance of the Au@Co@PtCoAu multilayer structure can be ascribed to the finely modulated electronic structure and the compensated composition loss owing to the delicate structure and composition profile design.