Optimizing the ORR performance of PtMnM ternary intermetallics by tuning the surface strain

Identifying the descriptors that control catalytic performance is key to design catalysts with high activity and stability. As indirect descriptors related to catalytic activity, modulating the Pt–Pt interatomic distance and d-band center can effectively enhance the ORR activity. It is well recognized that the Pt–Pt interatomic distance is strongly correlated with the surface strain. Herein, PtMnM/C ternary intermetallics are constructed through partially replacing Mn in PtMn/C binary intermetallics with the other transition metal (M = Fe, Co, Ni, and Cu). The 3d-transition metal doping induces surface strain, and the ORR performance of PtMnM/C exhibits volcano relationship relative to both the Pt–Pt interatomic distance and d-band center. The PtMnCo/C with optimum strain exhibits the highest mass activity (1.06 A mg_Pt⁻¹) at 0.9 V, which is 2.6 and 4.6 times higher than that of PtMn/C and commercial Pt/C catalysts, respectively. In addition, PtMnCo/C shows good durability with only 10 mV half-wave potential decay after 50,000 potential cycles.