Dual-Site Synergistic Mechanism via Single-Atom and Vacancy Drives Lattice Oxygen Activation in Layered Double Hydroxides

Establishing the synergistic effect between single atoms and vacancies for the lattice oxygen mechanism (LOM) pathway of the oxygen evolution reaction (OER) is crucial for developing robust and efficient catalysts, yet remains unexplored. Herein, an ion irradiation-assisted strategy is first applied to introduce controlled oxygen vacancies into NiFe layer double hydroxides (LDH), enabling the firm anchoring of Mo single atoms with a high loading of 7.4 wt.%. The precise regulation facilitates synergistic activation of lattice oxygen via Mo atoms and vacancies. Thus, the optimized ^SAMo-NiFe LDH/Ti delivers remarkably improved performance with a decrease of overpotential of 226 mV at 10 mA cm⁻² and, owing to the confinement effect of vacancies, maintains 600 h at 500 mA cm⁻². First-principles calculations reveal that Mo single atoms coupling with oxygen vacancies exhibit enhanced adsorption capability, and promote lattice oxygen activation, synergistically optimizing the electronic structure of active centers for OER. This study establishes a direct link between defect engineering, single-atom catalysis, and LOM, providing a robust strategy for rational catalyst design. © 2025 The Author(s).