Efficient Hydrogen Evolution on Cu Nanodots-Decorated Ni₃S₂ Nanotubes by Optimizing Atomic Hydrogen Adsorption and Desorption

TLDR

Low‑cost transition‑metal dichalcogenides (MS₂) are promising hydrogen‑evolution catalysts, but sulfur–hydrogen bond formation on MS₂ surfaces suppresses activity. This study reports Cu nanodot‑decorated Ni₃S₂ nanotubes on carbon fibers as efficient alkaline HER electrocatalysts. Cu nanodots become positively charged, promoting water adsorption and activation, while negatively charged Ni₃S₂ nanotubes weaken S–H bonds, optimizing hydrogen adsorption/desorption and enhancing Volmer and Heyrovsky steps. The Cu/Ni₃S₂ hybrid exhibits low onset potential, high catalytic activity, and excellent stability, outperforming conventional MS₂ catalysts.

Abstract

Low-cost transition-metal dichalcogenides (MS2) have attracted great interest as alternative catalysts for hydrogen evolution. However, a significant challenge is the formation of sulfur–hydrogen bonds on MS2 (S–Hads), which will severely suppress hydrogen evolution reaction (HER). Here we report Cu nanodots (NDs)-decorated Ni3S2 nanotubes (NTs) supported on carbon fibers (CFs) (Cu NDs/Ni3S2 NTs-CFs) as efficient electrocatalysts for HER in alkaline media. The electronic interactions between Cu and Ni3S2 result in Cu NDs that are positively charged and can promote water adsorption and activation. Meanwhile, Ni3S2 NTs are negatively charged and can weaken S–Hads bonds formed on catalyst surfaces. Therefore, the Cu/Ni3S2 hybrids can optimize H adsorption and desorption on electrocatalysts and can promote both Volmer and Heyrovsky steps of HER. The strong interactions between Cu and Ni3S2 cause the Cu NDs/Ni3S2 NTs-CFs electrocatalysts to exhibit the outstanding HER catalytic performance with low onset potential, high catalytic activity, and excellent stability.