Atomic-level engineering of lanthanum single atoms in Co3O4: Oxygen vacancy-mediated electronic modulation for catalytic oxidation reaction

Atomic-level engineering of the surface and electronic structure of Co 3 O 4 catalysts holds significant importance for both fundamental catalytic mechanisms and practical applications. In this study, well-defined La single atom-doped Co 3 O 4 catalysts were designed via an ion exchange process. Theoretical and experimental analyses demonstrate that single La atoms selectively substitute Co 3+ ions at octahedral sites in Co 3 O 4 . The larger ionic radius of La induces compressive strain on adjacent atoms, resulting in localized lattice distortion. To release the local tension, an asymmetric La–V o –Co site spontaneously forms. The coordination number of La decreases from 6 to 4.7 due to vacancy formation, leading to a reduced valence state and enhanced electron-donating propensity. Theoretical calculations reveal that single-atom La doping leads to an upshift of the Co 3 O 4 d-band center, thereby enhancing its interaction with oxygen. Besides, electrons from the 5d orbitals of La transfer to the π * antibonding orbitals of molecular oxygen during catalytic oxidation, thereby weakening the O–O bond strength and promoting oxygen dissociation. The single-atom La modified Co 3 O 4 catalyst exhibits remarkable catalytic activity in the oxidation of benzyl alcohol (BzOH), resulting in a 4.5-fold increase in conversion rate compared to unmodified Co 3 O 4 . The findings of our research provide a robust foundation for the characterization and comprehension of single-atom rare earth catalysts in heterogeneous oxidation reaction.