Stabilizing Ru Single Atoms on Asymmetric La/Co3O4 Supports with Strong Metal–Support Interaction for Efficient Acidic Water Oxidation

Exploring highly efficient and stable single-atom electrocatalysts for the oxygen evolution reaction (OER) is urgent for cost-effective hydrogen production by a proton exchange membrane water electrolyzer, but their stability is limited owing to the harsh corrosive and oxidative environments. Herein, we propose the synthesis of stable Ru single atoms (SAs) on the La-doped Co3O4 surface (Ru@La/Co3O4-20) via a strong metal–support interaction (SMSI), which exhibits a low overpotential at 10 mA cm–2 (η10: 244 mV) and a stability of 30 h (decay rate: 3.7 mV h–1) at 10 mA cm–2, outperforming Ru SAs on the Co3O4 surface (Ru@Co3O4) (η10: 295 mV; decay rate: 12.7 mV h–1) and benchmark RuO2. Experiments and density functional theory calculations demonstrate that electron transfer occurs from Ru SAs to asymmetric La/Co3O4 supports through bridge O atoms, strengthening the SMSI. Compared to Ru@Co3O4, the stronger SMSI between Ru SAs and asymmetric La/Co3O4 supports could help to adjust the Ru 4d and 2p band center’s location, which optimizes the adsorption of O intermediates and weakens Ru–O covalency, thus boosting the acidic OER activity and stability of Ru@La/Co3O4-20.