Promotion of alkaline hydrogen production via Ni-doping of atomically precise Ag nanoclusters

Alloy catalysts are widely used in electrocatalytic hydrogen production because of the synergistic effect produced by constituent metals. However, an atomic-level understanding of the alloy effect remains elusive because of their polydispersity. In this study, we investigated the effects of an atomically precise Ag₂₅ nanocluster catalyst doped with a single Ni atom in an alkaline electrolyte on the hydrogen evolution reaction (HER). The synthesized NiAg₂₄ nanoclusters exhibited significantly altered electronic structures and reduction potentials, leading to substantially reduced overpotentials and enhanced HER activity. Tafel analysis revealed that Ni doping drastically improved the sluggish Volmer step. Density functional theory studies further revealed that the hydrogen adsorption energy was substantially reduced upon Ni doping, which accounted for the enhanced HER activity observed for the NiAg₂₄ nanoclusters.