Engineering Bifunctional Oxygen Electrocatalysts in 2D Conjugated Metal–Organic Frameworks: Theoretical Perspectives on Metal–Ligand Synergistic Effects

Two-dimensional metal-organic frameworks (MOFs) provide a versatile platform for bifunctional oxygen electrocatalyst design by combining low-dimensionality with tunable active sites and coordination microenvironments. In this work, we evaluate the stability, selectivity, and oxygen catalytic activity of diverse MOFs with variable metal centers and coordination environments by first-principles calculations. The designed MOFs display deviation from conventional scaling between adsorption free energies of OH* and OOH* observed in face-centered metals, lowering the theoretical overpotential limit. Among them, 15 candidates surpass the IrO₂/Pt benchmark in overall OER/ORR activity. Electronic structure analysis reveals that synergistic modulation of metals and coordination environments alters the energy levels of metal <i>d</i> orbitals and antibonding occupancy, thereby tuning the intermediate binding. In addition, a gradient boosting model is developed to predict the adsorption free energies of intermediates solely on the basis of intrinsic features of active sites and corresponding microenvironments in these MOFs. These findings provide valuable theoretical insights into the structure-activity relationships in MOFs.