Structurally-Distorted RuIr-Based Nanoframes for Long-Duration Oxygen Evolution Catalysis.

Oxygen evolution reaction (OER) plays a key role in proton exchange membrane water electrolysis, yet the electrocatalysts still suffer from the disadvantages of low activity and poor stability in acidic conditions. Here, we have successfully fabricated a new class of CdRu 2 IrO x nanoframes with distorted structure for acidic OER. Impressively, CdRu 2 IrO x displays an ultralow overpotential of 189 mV and an ultralong stability of 1500 h at 10 mA cm -2 towards OER in 0.5 M H 2 SO 4 , which has generally outperformed the reported catalysts (overpotential ∼200 mV and stability < 500 h in general). Moreover, a proton-exchange membrane water electrolyser (PEMWE) using the distorted CdRu 2 IrO x can be steadily operated at 0.1 A cm -2 for 90 h. Microstructural analyses and X-ray absorption spectroscopy (XAS) demonstrate that the synergy between Ru and Ir in CdRu 2 IrO x induces the distortion of Ru-O, Ir-O, and Ru-M (M = Ru, Ir) bonds. In-situ XAS indicates that the applied potential leads to the deformation octahedral structure of RuO x /IrO x and the formation of stable Ru 5+ species for OER. Theoretical calculations also reveal that the distorted structures with shrunken Ru-O, Ir-O, and Ru-M (M = Ru, Ir) bonds can reduce the energy barrier of rate-limiting step during OER. This work provides an efficient strategy for constructing structural distortion to achieve significant enhancement on activity and stability of OER catalysts, which will attract immediate interests in diverse fields including materials, chemistry, and catalysis. This article is protected by copyright. All rights reserved.