Pore-Space-Partition-Oriented Sandwich Platinum Array Confined in a Metal-Organic Framework for Boosting Overall Water Splitting.

The atomic-level dispersion of noble metals in porous materials is prospective for highly efficient catalyst systems but is still inscrutable. Inspired by sandwich compounds, platinum (Pt) atoms were rationally confined within a metal-organic framework (MOF) through pore space partition by conjugate interactions between Pt and parallel-distributed aromatic pore partitioners, forming 1D infinite Pt arrays. By regulating the distance between adjacent aromatic rings from 7 to 4.5 to 3 Å (∼ the diameter of the Pt atom), the particle size in sandwich Pt arrays decreased in a linear fashion with the Pt electronic orbital simultaneously regulated by a pore partitioner, MOF nodes, and near noble atoms, as revealed by AC high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and theoretical simulations. The optimized MOF pore endows the Pt@MOF-BCP material with highly efficient utilization of Pt sites, best electron transmission efficiency, and excellent catalytic stability. At 10 mA·cm, an optimal Pt@MOF-BCP catalyst only needs ultralow overpotentials of 2.5 mV for hydrogen evolution reaction in the acidic electrolyte and 265 mV for oxygen evolution reaction in the alkaline electrolyte, exhibiting exceptional difunctional electrocatalytic performance superior to most benchmark catalysts. Remarkably, the cell voltage of Pt@MOF-BCP was dramatically reduced to 1.47 V at 10 mA·cm in practical application.