Ruthenium Single-Atom Modulated Protonated Iridium Oxide for Acidic Water Oxidation in Proton Exchange Membrane Electrolysers.

Tang, Jialin; Liu, Xinyan; Xiong, Xiaoxia; Zeng, Qisheng; Ji, Yuan; Liu, Chunxiao; Li, Jiawei; Zeng, Hongliang et al. · Adv Mater · 2024

basic_science · Level V

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Abstract

Proton exchange membrane water electrolysers promise to usher in a new era of clean energy, but they remain a formidable obstacle in designing active and durable electrocatalysts for the acidic oxygen evolution reaction (OER). In this study, a protonated iridium oxide embedded with single-atom dispersed ruthenium atoms (H<sub>3.8</sub>Ir<sub>1-</sub> <sub>x</sub>Ru<sub>x</sub>O<sub>4</sub>) that demonstrates exceptional activity and stability in acidic water oxidation is introduced. The single Ru dopants favorably induce localized oxygen vacancies in the Ir─O lattice, synergistically strengthening the adsorption of OOH* intermediates and enhancing the intrinsic OER activity. In addition, the preferential oxidation of Ru and the electronegativity of the oxygen vacancies significantly stabilize the Ir─O active sites, improving the OER stability. Consequently, the H<sub>3.8</sub>Ir<sub>1─</sub> <sub>x</sub>Ru<sub>x</sub>O<sub>4</sub> catalyst shows an overpotential of 255 mV at 10 mA cm<sup>-2</sup> and displays exceptional catalytic endurance in acidic electrolytes, surpassing 1100 h, representing a remarkable one-order-of-magnitude increase in stability compared to that of pristine H<sub>3.8</sub>IrO<sub>4</sub>. A proton exchange membrane electrolyser utilizing the H<sub>3.8</sub>Ir<sub>1-</sub> <sub>x</sub>Ru<sub>x</sub>O<sub>4</sub> catalyst as an anode exhibits stable performance for more than 1280 h under a high current density of 2 A cm<sup>-2</sup>.