Addressing major challenges from the material cost, efficiency and stability, it is highly desirable to develop high-performance catalysts for oxygen evolution reaction (OER). Herein we explore a facile surfactant-assisted approach for fabricating Ir-Sn (Ir/Sn = 0.6/0.4, by mol.) nano-oxide catalysts with good morphology control. Direct proofs from XRD and X-ray photoelectron spectra indicate hydrophilic triblock polymer (TBP, like Pluronic (R) F108) surfactant can boost the formation of stable solid-solution structure. With the TBP hydrophilic and block-length increase, the fabricated Ir-Sn oxides undergoing the rod-to-sphere transition obtain the relatively lower crystallization, decreased crystallite size, Ir-enriched surface and incremental available active sites, all of which can bolster the OER activity and stability. Meanwhile, it is observed that the coupled Ir oxidative etching takes a crucial role in determining the material structure and performance. Compared with commercial Ir black, half-cell tests confirm F108-assistant catalysts with over 40 wt% Ir loading reduction show 2-fold activity enhancement as well as significant stability improvement. The lowest cell voltage using 0.88 mg cm(-2) Ir loading is only 1.621 V at 1000 mA cm(-2) and 80 degrees C with a concomitant energy efficiency of 75.8% which is beyond the DOE 2017 efficiency target of 74%. (C) 2016 Elsevier B.V. All rights reserved.