Metal-organic framework derived ellipse-like NiS2 nanocatalyst for stable electrochemical hydrogen generation in alkaline electrolyte

The development of non-precious and high-efficient electrocatalysts to enhance the activity and stability in alkaline media is impending for massive hydrogen and oxygen production. In this study, NiS 2 nanoparticles array with ellipse-like topography was fabricated via simple hydrothermal and sulfurization treatment. The NiS 2 -400 featured with the unique loose stacking topographic architecture contributes to more exposed active sites, the smaller contact resistance between electrode/electrolyte, faster ion diffusion and electron transfer . As a result, NiS 2 -400 electrode requires only overpotentials of 116 and 178 mV to drive current densities of 10 and 50 mA cm −2 in 1.0 M KOH towards the hydrogen evolution reaction (HER), coupled with a Tafel slope of 93.0 mV dec −1 . Moreover, the resultant NiS 2 -400 nanoparticles exhibit excellent electrochemical stability for more than 50 h. In addition, the density functional theory (DFT) calculation further confirms that the (200) facet acts as the predominant active site, contributing to the enhanced HER performance.