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

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