In present work, truncated octahedral Pt-Ni-Ir ternary nanoparticles with an average size of 10 nm and a Pt/Ni/Ir atomic ratio of 55/29/16 are synthesized through a facile method. Structural measurements show that the nanoparticles are surface Ni-scarce Pt-Ni-Ir ternary nanostructures. The mass activity and specific activity of the ternary catalyst are 511 mA mg(-1) (Pt) and 1.03 mA cm(-2) at 0.9 V (vs. reversible hydrogen electrode, RHE), respectively, which are nearly 4.8 and 6.0 times larger than that of the commercial Pt/C catalyst (106 mA mg(-1) and 0.17 mA cm(-2)). After duration test of 10,000 cycles at the potential range from 0.6 to 1.0 V, the ternary catalyst preserved 66% and 73% of its initial mass activity and specific activity, respectively, which are 9 and 7.6 times that of the commercial Pt/C catalyst (37.2 mA mg(-1) and 0.0998 mA cm(-2), respectively) after the same durability examination. The dramatic enhancement of Pt-Ni-It ternary catalyst can be attributed to its morphology, composition and nanostructure. Our research suggests that Pt-Ni-It ternary catalyst could be an excellent candidate for ORR. Our investigation might also spur increasing attention to tailoring morphology and composition of ternary or multi-metallic nanostructure with high electro-catalytic performance. (C) 2015 Elsevier B.V. All rights reserved.