In Situ Immobilizing Atomically Dispersed Ru on Oxygen-Defective Co3O4 for Efficient Oxygen 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 coex-istence 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 oxygen evolution.

Automated summary

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. In this study, 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. The as-prepared Ru/Co3O4-x electrocatalyst with the coexistence of oxygen vacancies and Ru atoms exhibits excellent performances toward OER.