A Co-Doped Nanorod-like RuO2 Electrocatalyst with Abundant Oxygen Vacancies for Acidic Water Oxidation

Abstract

Active and highly stable electrocatalysts for oxygen evolution reaction (OER) in acidic media are currently in high demand as a cleaner alternative to the combustion of fossil fuels. Herein, we report a Co-doped nanorod-like RuO₂ electrocatalyst with an abundance of oxygen vacancies achieved through the facile, one-step annealing of a Ru-exchanged ZIF-67 derivative. The compound exhibits ultra-high OER performance in acidic media, with a low overpotential of 169 mV at 10 mA cm^-2 while maintaining excellent activity, even when exposed to a 50-h galvanostatic stability test at a constant current of 10 mA cm^-2. The dramatic enhancement in OER performance is mainly attributed to the abundance of oxygen vacancies and modulated electronic structure of the Co-doped RuO₂ that rely on a vacancy-related lattice oxygen oxidation mechanism (LOM) rather than adsorbate evolution reaction mechanism (AEM), as revealed and supported by experimental characterizations as well as density functional theory (DFT) calculations.