N-doped carbon embedded Ni3S2 electrocatalyst material towards efficient hydrogen evolution reaction in broad pH range

Abstract

The synthesis of extremely stable and active earth abundant electrocatalyst is necessary to minimize the reliance on platinum (Pt) for hydrogen evolution reaction (HER) over broad pH medium which is remaining as a great challenge. Among different ordinary metal based electrocatalysts, nickel sulphide-based material has been recognized as active electrocatalyst due to its more active edge and high stability. Herein, nickel sulphide with nitrogen doped carbon (Ni3S2/NC) composites electrocatalyst have been prepared with different weight contents (Ni3S2/NC10, Ni3S2/NC20, Ni3S2/NC30 and Ni3S2/NC40) of NC via a simple hydrothermal one-step approach to evaluate the HER activity. The morphological and structural properties of the synthesized electrocatalysts were characterized using FTIR, XRD, SEM, HR-TEM and EDAX. The SEM of the synthesized Ni3S2/NC20 composite has shown nanocube like structure. Additionally, the electrochemical behaviour was evaluated over a broad pH medium to assess the HER activity of the synthesized materials. The obtained electrochemical results displayed that the Ni3S2/NC20 composite showed a good activity with the overpotential value of 174, 199 and 249 mV in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M phosphate buffer solution (PBS) at 10 mA cm−2, respectively. This optimized composition exhibited an efficient stability for 1000 cycles and durability for 15 h in broad pH medium. Hence, the chosen Ni3S2/NC20 electrocatalyst will be a less expensive non-Pt based electrocatalyst for efficient HER.