Lattice oxygen regeneration achieved on Ho-doped CoFeO for enhanced oxygen evolution performance

The lattice oxygen mechanism (LOM) is recognized as a kinetic-favored pathway for oxygen evolution during water oxidation. However, the imbalance between lattice oxygen consumption and regeneration limits the long-term stability and lifespan of electrocatalysts. In this study, we present a CoFeHoO catalyst characterized by enhanced OH adsorption at oxygen vacancy sites, which facilitates the regeneration of lattice oxygen and consequently improves durability. Using isotope-labeled ( 18 O) in situ differential electrochemical mass spectrometry (DEMS), pH-dependent oxygen evolution kinetics, and TMA + probing, we demonstrate that the incorporation of Ho into CoFe oxyhydroxide enhances oxygen regeneration during the LOM cycle. In situ Fourier-transform infrared spectroscopy (FT-IR) and density functional theory (DFT) calculations further confirmed the improved OH adsorption energy at the oxygen vacancy sites on the CoFeHoO slab. This work offers a rational design strategy for developing highly efficient LOM-based electrocatalysts.