Unraveling oxygen vacancy site mechanism of Rh-doped RuO<sub>2</sub> catalyst for long-lasting acidic water oxidation.

Wang, Yi; Yang, Rong; Ding, Yajun; Zhang, Bo; Li, Hao; Bai, Bing; Li, Mingrun; Cui, Yi et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Exploring durable electrocatalysts with high activity for oxygen evolution reaction (OER) in acidic media is of paramount importance for H<sub>2</sub> production via polymer electrolyte membrane electrolyzers, yet it remains urgently challenging. Herein, we report a synergistic strategy of Rh doping and surface oxygen vacancies to precisely regulate unconventional OER reaction path via the Ru-O-Rh active sites of Rh-RuO<sub>2</sub>, simultaneously boosting intrinsic activity and stability. The stabilized low-valent catalyst exhibits a remarkable performance, with an overpotential of 161 mV at 10 mA cm<sup>-2</sup> and activity retention of 99.2% exceeding 700 h at 50 mA cm<sup>-2</sup>. Quasi in situ/operando characterizations demonstrate the recurrence of reversible oxygen species under working potentials for enhanced activity and durability. It is theoretically revealed that Rh-RuO<sub>2</sub> passes through a more optimal reaction path of lattice oxygen mediated mechanism-oxygen vacancy site mechanism induced by the synergistic interaction of defects and Ru-O-Rh active sites with the rate-determining step of *O formation, breaking the barrier limitation (*OOH) of the traditional adsorption evolution mechanism.