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.