Composition tunable ternary Pt–Ni–Co octahedra for optimized oxygen reduction activity

Herein, we report a one-step synthesis method for octahedral Pt–Ni–Co ternary catalysts with tunable compositions and fixed shapes. Impressively, the composition optimized octahedral PtNi0.55Co0.1/C demonstrated a significant improvement in ORR activity compared to those of previously reported Pt–Ni–Co alloy octahedra, showing an outstanding specific activity of 5.05 mA cm−2 and a mass activity of 2.80 mA μgPt−1, which are around 20.2 times and 14.7 times higher than those of the commercial Pt/C catalyst (0.25 mA cm−2 and 0.19 mA μgPt−1).