Subnanometric Pt–W\nBimetallic Clusters for\nEfficient Alkaline Hydrogen Evolution Electrocatalysis

Rational design and synthesis of subnanometric bimetallic\nclusters\n(SBCs) within a narrow size distribution, along with achieving full\nSBCs exposure on supporting materials, are formidable challenges that\nmust be overcome to realize potential applications. This work details\na facile strategy to synthesize fully exposed PtW SBCs with an average\nsize of 0.81 nm on the surface of spherical N-doped carbon (PtW/NC),\nwhich is underpinned by the electrostatic interactions between the\nnegatively charged [H<sub>3</sub>PtW<sub>6</sub>O<sub>24</sub>]<sup>5–</sup> polyanions and the positively charged closed-pore\nmetal–organic framework (MOF) [Zn<sub>5</sub>(OH)<sub>2</sub>(AmTRZ)<sub>6</sub>]<sup>2+</sup>. The PtW/NC exhibits significant\nelectrocatalytic performance and stability for the alkaline hydrogen\nevolution reaction with an ultralow overpotential of 4 mV at 10 mA\ncm<sup>–2</sup>, a low Tafel slope of 29 mV dec<sup>–1</sup>, and a long-term electrolysis stability exceeding 140 h. The Pt\nmass activity of PtW/NC is 34 times higher than that of commercial\n20 wt % Pt/C at the 100 mV overpotential. Both theoretical calculations\nand electrochemical measurements indicate that a synergistic effect\nbetween Pt and W is responsible for this notable catalytic performance.\nThe synthetic approach outlined in this work can be applied to other\nMOFs and coordination networks that lack pores or have limited porosity.