Rational Construction of Co 4 (μ-O) 6 (COO) 6 SBU-Based MOFs through Mixed-Ligand Strategy to Enhance Electrocatalytic Oxygen Evolution Performance.

Metal-organic frameworks (MOFs) are increasingly becoming an important choice for developing robust and efficient electrocatalysts; therefore, exploring the relationship between the structure, catalytic activity, and stability of MOFs is of great significance. MOFs 1 - 3 with different spatial configurations are designed and synthesized based on linear pyridine ligands, tetragonal carboxylic acid ligands, and triangular carboxylic acid ligands, while MOF 4 displays a three-dimensional (3D) supramolecule assembled through a mixed-ligand strategy. Compared with MOFs 1 - 3 , MOF 4 has the lowest overpotential of 106 mV (at 10 mA·cm ^-2 ) and a Tafel slope of 80.9 mV·dec ^-1 , as well as sturdy long-term stability in the process of oxygen evolution reaction (OER). The presence of dense metal clusters and μ ₃ -O promotes the optimal catalytic performance of MOF 4 . Density functional theory (DFT) calculations of MOF 4 demonstrate that the process from O* to OOH* is the rate-determining step. This investigation further reveals the relationship between MOF structural composition and electrocatalytic OER performance and provides an effective strategy for the assembly of MOF-based electrocatalysts.