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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.

Converting CO 2 to valuable chemicals and fuels is a viable method to establish a carbon-neutral energy cycle in the environment. Metal-organic frameworks (MOFs), characterized by dispersed active sites, high porosity, etc., have displayed a great application prospect in the electrochemical/chemical CO 2 reduction reaction (CO 2 RR) process. Herein, we proposed a one-step production to establish a series of pillar-layered porous MOFs, [Co 2 (L)(bimb)] n (MOF 1 ) and [Co 4 (L) 2 (bidpe) 2 ] n (MOF 2 ) [H 4 L = 5'-(4-carboxyphenyl)-(1,1':2',1″-terphenyl)-4,4',4″-tricarboxylic, bimb = 1,4-bis(imidazol-1-yl)-butane, bidpe = 4'-bis(imidazolyl) diphenyl ether], for preferential conversion of CO 2 via ligand adjustment and increase of active sites' density. According to single-crystal X-ray diffraction studies, [Co 2 (L)(bimb)] n exhibits pillar-layered binuclear 3D frameworks with a 2,4,6-linked 3-nodes new topology structure, while [Co 4 (L) 2 (bidpe) 2 ] n displays pillar-layered tetranuclear interspersed networks with a 4,6-linked 2-nodes fsc topology structure through a ligand adjustment strategy. Meanwhile, the pillar-layered structure of the MOFs with abundant active sites is conducive to mass diffusion and benefits the conversion of CO 2 . MOFs 1 - 2 exhibit good electrocatalytic activity for CO 2 RR in 0.5 M KHCO 3 solution. Especially, the current density of MOF 2 generated at -0.90 V (vs. RHE) reaches -81.6 mA·cm -2 , which is 3.1 times higher than that under an Ar atmosphere. In addition, MOFs 1 - 2 can be used as a heterogeneous catalyst for chemical conversion of CO 2 . The results are expected to provide inspiration for rational design to develop stable and high-efficiency MOF-based electrocatalysts for CO 2 RR.