Rational Construction\nof Co<sub>4</sub>(μ-O)<sub>6</sub>(COO)<sub>6</sub> SBU-Based\nMOFs through Mixed-Ligand Strategy\nto Enhance Electrocatalytic Oxygen Evolution Performance

Metal–organic frameworks (MOFs) are increasingly\nbecoming\nan important choice for developing robust and efficient electrocatalysts;\ntherefore, exploring the relationship between the structure, catalytic\nactivity, and stability of MOFs is of great significance. MOFs <b>1</b>–<b>3</b> with different spatial configurations\nare designed and synthesized based on linear pyridine ligands, tetragonal\ncarboxylic acid ligands, and triangular carboxylic acid ligands, while\nMOF <b>4</b> displays a three-dimensional (3D) supramolecule\nassembled through a mixed-ligand strategy. Compared with MOFs <b>1</b>–<b>3</b>, MOF <b>4</b> has the lowest\noverpotential of 106 mV (at 10 mA·cm<sup>–2</sup>) and\na Tafel slope of 80.9 mV·dec<sup>–1</sup>, as well as\nsturdy long-term stability in the process of oxygen evolution reaction\n(OER). The presence of dense metal clusters and μ<sub>3</sub>-O promotes the optimal catalytic performance of MOF <b>4</b>. Density functional theory (DFT) calculations of MOF <b>4</b> demonstrate that the process from O* to OOH* is the rate-determining\nstep. This investigation further reveals the relationship between\nMOF structural composition and electrocatalytic OER performance and\nprovides an effective strategy for the assembly of MOF-based electrocatalysts.