Modulating the Electronic Structures of Co-Based Spinel Compounds via Rare Earth Tetrad Effect

-plane and the Z-direction induced by RE. In addition, RE achieve dual-periodic regulation of the Co valence state through 4f-5d-6s-5p orbital hybridization to attain a state where the 4f orbitals are nearly half-filled. The relationship between the regulation mechanism of the RE tetrad effect on the electronic structure and the adsorption evolution of oxygen-containing species has been established. Finally, we have presented a design strategy for RE composite systems based on the tetrad effect, which plays a crucial role in achieving the accurate selection and efficient utilization of RE.