Inducing a\nSynergistic Effect on Pt<sup>δ+</sup>/Electron-Rich Sites via\na Platinization Strategy: Generating Hyper-High\nCurrent Density in Hydrogen Evolution Reaction

Herein, we propose a platinization strategy for the preparation\nof Pt/X catalysts with low Pt content on substrates possessing electron-rich\nsites (Pt/X: X = Co<sub>3</sub>O<sub>4</sub>, NiO, CeO<sub>2</sub>, Covalent Organic Framework (COF), etc.). In examples with inorganic\nand organic substrates, respectively, Pt/Co<sub>3</sub>O<sub>4</sub> possesses remarkable catalytic ability toward HER, achieving a current\ndensity at an overpotential of 500 mV that is 3.22 times higher than\nthat of commercial Pt/C. It was also confirmed by using <i>operando</i> Raman spectroscopy that the enhancement of catalytic activity was\nachieved after platinization of the COF, with a reduction of overpotential\nfrom 231 to 23 mV at 10 mA cm<sup>–2</sup>. Density functional\ntheory (DFT) reveals that the improved catalytic activity of Pt/Co<sub>3</sub>O<sub>4</sub> and Pt/COF originated from the re-modulation\nof Pt<sup>δ+</sup> on the electronic structure and the synergistic\neffect of the interfacial Pt<sup>δ+</sup>/electron-rich sites.\nThis work provides a rapid synthesis strategy for the synthesis of\nlow-content Pt catalysts for electrocatalytic hydrogen production.