Tailoring the electron redistribution of RuO2 by constructing a Ru-O-La asymmetric configuration for efficient acidic oxygen evolution

Abstract

Stabilizing the highly active RuO 2 electrocatalyst for the oxygen evolution reaction (OER) is critical for the application of proton exchange membrane water electrolysis, but this remains challenging due to the inevitable over-oxidation of Ru in harsh oxidative environments. Herein, we describe constructing Ru-O-La asymmetric configurations into RuO 2 via a facile sol-gel method to tailor electron redistribution and thereby eliminate the over-oxidation of Ru centers. Specifically, the as-prepared optimal La 0.1 Ru 0.9 O 2 shows a low overpotential of 188 ​mV at 10 ​mA ​cm −2 , a high mass activity of 251 A g Ru − 1 at 1.6 ​V vs. reversible hydrogen electrode (RHE), and a long-lasting durability of 63 ​h, far superior to the 8 ​h achieved by standard RuO 2 . Experiments and density functional theory calculations jointly reveal that the Ru-O-La asymmetric configuration could trigger electron redistribution in RuO 2 . More importantly, electron transfer from La to Ru via the Ru-O-La configuration could lead to increased electron density around Ru, thus preventing the over-oxidation of Ru. In addition, electron redistribution tunes the Ru 4d band center’s energy level, which optimizes the adsorption and desorption of oxygen intermediates. This work offers an effective strategy for regulating electronic structure to synergistically boost the activity and stability of RuO 2 -based acidic OER electrocatalysts. • Ru-O-La asymmetric configurations have been constructed into RuO 2 to tailor electron redistribution of Ru centers. • The optimal La 0.1 Ru 0.9 O 2 displays lower overpotential and better long-term stability than RuO 2 . • The electron transfer from La to Ru eliminates over-oxidation of RuO 2 . • In situ techniques results demonstrate La 0.1 Ru 0.9 O 2 follows the adsorption evolution mechanism pathway.

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