p-d hybridization in CoFe LDH nanoflowers for efficient oxygen evolution electrocatalysis

Zeolite imidazolate framework-67 (ZIF-67)-derived layered double hydroxides (LDHs) via hydrolysis reactions have aroused widespread interest in the oxygen evolution reaction (OER), while the role of the electron-deficient 2-methylimidazole (MIM) of ZIF-67 in the boosted OER activity of LDHs has been largely overlooked. In this work, the influence of electron-deficient organic ligands on the electronic structures of catalytic sites and the OER performance of CoFe LDH are systematically elucidated. The experimental and theoretical calculation results reveal that the organic ligand triggers the p-d orbital hybridization at the interface of CoFe LDH/MIM, resulting in a downshift of the d-band center of CoFe LDH and the optimization of the binding strength of intermediates during the OER, which gives deep insights into understanding the excellent OER activity of metal-organic framework-derived LDHs.