In Situ Immobilizing Atomically Dispersed Ru on Oxygen-Defective for Efficient Evolution

The synergistic regulation of the electronic structures of transition-metal oxide-based catalysts via oxygen vacancy defects and single atom doping is efficient to boost their oxygen evolution reaction (OER) performance, which remains challenging due to complex synthetic procedures. Herein, a facile defect-induced in situ single-atom deposition strategy is developed to anchor atomically dispersed Ru single-atom onto oxygen vacancy-rich cobalt oxides (Ru/Co3O4-x) based on the spontaneous redox reaction between Ru3+ ions and nonstoichiometric Co3O4-x. Accordingly, the as-prepared Ru/Co3O4-x electrocatalyst with the coexistence of oxygen vacancies and Ru atoms exhibits excellent performances toward OER with a low overpotential of 280 mV at 10 mA cm-2, a small Tafel slope value of 86.9 mV dec-1, and good long-term stability in alkaline media. Furthermore, density functional theory calculations uncover that oxygen vacancy and atomically dispersed Ru could synergistically tailor electron decentralization and d-band center of Co atoms, further optimizing the adsorption of oxygen-based intermediates (*OH, *O, and *OOH) and reducing the reaction barriers of OER. This work proposes an available strategy for constructing electrocatalysts with abundant oxygen vacancies and atomically dispersed noble metal and presents a deep understanding of synergistic electronic engineering of transition-metal-based catalysts to boost evolution.

Automated summary

The synergistic regulation of electronic structures of transition-metal oxide-based catalysts using oxygen vacancy defects and single atom doping can significantly enhance their performance in oxygen evolution reaction (OER). In this study, a simple defect-induced in situ single-atom deposition strategy was developed to deposit atomically dispersed Ru single atoms onto oxygen vacancy-rich cobalt oxides (Ru/Co3O4-x) by a spontaneous redox reaction. The resulting Ru/Co3O4-x electrocatalyst, with the coexistence of oxygen vacancies and Ru atoms, exhibited excellent OER performance with a low overpotential, small Tafel slope value, and good long-term stability in alkaline media. Density functional theory calculations revealed that the synergy between oxygen vacancies and atomically dispersed Ru can optimize the adsorption of oxygen-based intermediates and reduce the reaction barriers of OER by tailoring the electron decentralization and d-band center of Co atoms. This study proposes a feasible strategy for constructing electrocatalysts with abundant oxygen vacancies and atomically dispersed noble metals, and provides a deep understanding of the electronic engineering of transition-metal-based catalysts to boost OER.