Encapsulation of Ferrocene Methylamine in a Metal–Organic Framework for Enhanced Oxygen Evolution Reaction

2D conductive Metal–organic frameworks (MOFs) have emerged as promising electrocatalysts. Their unique conjugated structure leads to rapid electron transfer rates and confers excellent electrical conductivity. However, the electrocatalysis environments always involve complicated multiphase interactions. The electrocatalytic efficiencies for 2D MOF are often hampered by low electrical conductivity in solvation and improper adsorption/desorption energy of intermediates, which refers to the electron transfer efficiency between the solid catalysts and solution, as well as the solid catalysts and the gas molecules. In this study, we addressed these limitations by encapsulating guest molecules into the hexagonal nanocavity of 2D MOF. Fc-Ni-HHTP was synthesized by introducing ferrocene derivatives (ferrocene methylamine, Fc-NH2) into Ni-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene). It exhibited superior performance in the oxygen evolution reaction (OER) compared to Ni-HHTP, with an overpotential of 482 mV at a current density of 10 mA cm–2, demonstrating excellent electrochemical stability. Density functional theory (DFT) calculations showed that the remarkable electrocatalytic performance of Fc-Ni-HHTP was attributed to the synergistic effect between the ferrocene derivatives and the Ni-HHTP matrix. This work provides a notable way to enhance the electrocatalytic performance of MOFs by introducing a guest molecule into a MOF to improve the multiphase electron transfer rates.