Synthesis of MoS2/Ni3S2 heterostructure for efficient electrocatalytic hydrogen evolution reaction through optimizing the sulfur sources selection

Abstract

The electrocatalysts with low-cost, good stabilities, rich reserves and efficient activities are required to replace Pt-based materials for the hydrogen evolution reaction. Herein, we synthesize the low-cost MoS2/Ni3S2 heterostructure on Ni foam with efficient HER activity and good stability through optimizing the sulfur sources selection among thioacetamide (TAA), L-cysteine and thiourea. The different sulfur sources have a very important influence on the structures and morphologies of NF-MoS2/Ni3S2 composites, which may attribute to the different selective combining capacities of sulfur sources with Na2MoO4 and Ni foam. By contrast, NF-MoS2/Ni3S2-TAA shows relatively lower overpotential of 91 mV at 10 mA cm−2 and Tafel slope of 48.62 mV dec−1 than those of NF-MoS2/Ni3S2-L-cysteine (overpotential of 148 mV at 10 mA cm−2 and Tafel slope of 68.81 mV dec−1) or NF-MoS2/Ni3S2-thiourea (overpotential of 187 mV at 10 mA cm−2 and Tafel slope of 93.41 mV dec−1). The superior HER activity of NF-MoS2/Ni3S2-TAA is benefit from the higher MoS2 content and larger electrochemically active surface area. Optimizing the sulfur source selection can realize the efficient electrocatalytic hydrogen evolution of MoS2/Ni3S2 heterostructure which has an important guiding significance for the practical application in the future.