Quadruple perovskite ruthenate as a highly efficient catalyst for acidic water oxidation.

Miao, Xianbing; Zhang, Lifu; Wu, Liang; Hu, Zhenpeng; Shi, Lei; Zhou, Shiming · Nat Commun · 2019

basic_science · Level V

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Abstract

Development of highly active and durable oxygen-evolving catalysts in acid media is a major challenge to design proton exchange membrane water electrolysis for producing hydrogen. Here, we report a quadruple perovskite oxide CaCu<sub>3</sub>Ru<sub>4</sub>O<sub>12</sub> as a superior catalyst for acidic water oxidation. This complex oxide exhibits an ultrasmall overpotential of 171 mV at 10 mA cm<sup>-2</sup><sub>geo</sub>, which is much lower than that of the state-of-the-art RuO<sub>2</sub>. Moreover, compared to RuO<sub>2</sub>, CaCu<sub>3</sub>Ru<sub>4</sub>O<sub>12</sub> shows a significant increase in mass activity by more than two orders of magnitude and much better stability. Density functional theory calculations reveal that the quadruple perovskite catalyst has a lower Ru 4d-band center relative to RuO<sub>2</sub>, which effectively optimizes the binding energy of oxygen intermediates and thereby enhances the catalytic activity.