Strong Electron Coupling Effect at the CoO/CeO₂ Interface Enables Efficient Oxygen Evolution Reaction

CeO2 has played an important role in improving the oxygen evolution reaction (OER) performance of transition metals-based catalysts whether as a hybrid, substrate, or interface. The high OER activity is ascribed to the optimized transition metals and/or the formed oxygen vacancies. In this work, the interface effect between CoO and CeO2 is reported to be the reason for the excellent OER performance of CoO/CeO2. Compared with sole CoO or CoO/CeO2-L (larger CoO nanosheets), CoO/CeO2 has exhibited higher OER performance due to the faster kinetics and higher OER intrinsic activity because of the large amount of Co/Ce interfaces. Theoretical calculations reveal the generation of the reconstructed active center of the Co–O–Ce configuration due to the strong electron coupling effect between CeO2 and CoO. The Co–O–Ce hybridization at the interface brings in the unoccupied oxygen states, acting as the acceptor-like states and optimizing the bonding energy with OER intermediates. The findings give an avenue to design excellent CeO2-containing OER catalysts through interface control.