Single Atoms Induced Pt Nanoclusters Promoting Hydrogen Evolution Reaction Under Ampere-Level Current Density

Pt is a widely recognized catalyst for the alkaline hydrogen evolution reaction (HER), but its high cost and scarcity hinder its large-scale industrial application to date. In this work, we report an S, N co-doped carbon (SNC) supported amorphous nanocluster (NCs) composite catalyst (Pt_n+Pt₁-SNC/NF) composed of Pt NCs encircled by a multitude of Pt single atoms (SAs). The Pt_n+Pt₁-SNC/NF was synthesized by an etching method using nitrogen-doped carbon-coated nickel foam (ppy/NF) as the substrate. Compared to commercial Pt/C, the catalyst exhibits a low HER overpotential (only 19 mV at 10 mA cm^-2) in 1 M KOH, a mass activity nearly four times higher than that of commercial Pt/C (115.4 A mg^-1 Pt at 100 mV), and excellent stability under high current density (up to 500 h). Systematic spectroscopic characterization reveals that the defective carbon substrate adsorbs and activates water molecules, leading to an increased relative concentration of activated water on the catalyst surface. The Pt SAs promote the adsorption and transfer of water molecules to the NCs surface, while the Pt NCs facilitate subsequent water dissociation and OH^- desorption. The theoretical findings align well with experimental outcomes. This work offers a promising strategy to develop high-efficiency and low-cost noble metal-based electrocatalysts toward practical hydrogen evolution.