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

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-H_ads), 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-H_ads 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.