Ru Single Atoms Integrated into Cobalt Oxide Spinel Structure with Interstitial Carbon for Enhanced Electrocatalytic Water Oxidation

Oxygen evolution reaction (OER) plays a critical role in energy conversion technologies. Significant progress has been made in alkaline conditions. In contrast, it remains a challenge to develop stable OER electrocatalysts in acidic conditions. Herein, a new strategy is reported to stabilize single atoms integrated into cobalt oxide spinel structure with interstitial carbon (Ru_0.27Co_2.73O₄), where the optimized Ru_0.27Co_2.73O₄ exhibits a low overpotential of 265, 326, and 367 mV to reach a current density of 10, 50, and 100 mA cm², respectively. More importantly, Ru_0.27Co_2.73O₄ has long-term stability of up to 100 h, representing one of the most stable OER electrocatalysts. X-ray adsorption spectroscopy (XAS) characterization and density functional theory (DFT) calculations jointly demonstrate that the significant catalytic performance of Ru_0.27Co_2.73O₄ is due to the synergistic effect between the Ru and Co sites and the bridging O ligands, as well as the significant reduction of the OER energy barrier. This work provides a new perspective for designing and constructing efficient non-noble metal-based electrocatalysts for water splitting.