Tetrahydroxybenzoquinone-Based Two-Dimensional Conductive\nMetal–Organic Framework via π‑d Conjugation Modulation\nfor Enhanced Oxygen Evolution Reaction

2D\nconductive metal–organic frameworks (2D c-MOFs) have\nattracted significant interest as efficient electrocatalysts for the\noxygen evolution reaction (OER). However, effectively regulating their\ncatalytic activity remains a significant challenge. Herein, density\nfunctional theory (DFT) was performed to explore the effect of π-d\nconjugation modulation on the electronic structure of the tetrahydroxy-1,4-benzoquinone-based\n2D c-MOFs. The computational results indicate that the strong π-d\nconjugation caused by orbital hybridization between Co and Fe widens\nand enhances the hybridization between the d<sub><i>xz</i></sub>/d<sub><i>yz</i></sub> orbitals at the metal sites\nand the p orbitals of the ligands, thereby affecting the reconstruction\nof the MOFs during the OER process. Experimentally, CoFe-THQ with\nvarious atomic ratios was synthesized. The results indicated that\nthe synthesized Co<sub>0.6</sub>Fe<sub>0.4</sub>-THQ powders only\nneeds an overpotential of 247 mV to reach a current density of 10\nmA cm<sup>–2</sup> for the OER in alkaline medium, which is\nmuch lower than most reported transition metal-based electrocatalysts\nand even better than that of the benchmark RuO<sub>2</sub> electrocatalyst.\nFurthermore, in situ Raman and in situ Fourier transform infrared\nspectroscopy analyses revealed that Co<sub>0.6</sub>Fe<sub>0.4</sub>-THQ undergoes a different reconstruction evolution during the OER\nprocess compared to Co-THQ, with the mixed (Co, Fe) bimetallic oxides\n((Co, Fe)<sub>3</sub>O<sub>4</sub> and α-(Co, Fe)<sub>2</sub>O<sub>3</sub>) formed after reconstruction identified as the true\nactive species. This study opens up an effective avenue for the rational\ndesign of high-activity 2D c-MOF electrocatalysts.