Nanoporous Ni3S2 Film on Ni Foam as Highly Efficient Electrocatalyst for Hydrogen Evolution in Acidic Electrolyte

In this work, nanoporous Ni3S2 film (Ni3S2/Ni) is in situ synthesized by direct sulfurization of Ni foam under a mild hydrothermal process. Surprisingly, it is found out that the obtained Ni3S2/Ni exhibits outstanding HER activity and excellent stability in acidic electrolyte. The structure and nature of the Ni3S2/Ni are analyzed with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM). On Ni3S2/Ni, the onset potential is only −6.23 mV (vs. RHE) while the large exchange current density is 790 µA cm−2 and the Tafel slope is 62.47 mV dec−1. The experimental results demonstrate the potential of Ni3S2/Ni for its replacement of Pt-based catalysts.