Morphology-optimized interconnected Ni3S2 nanosheets coupled with Ni(OH)2 nanoparticles for enhanced hydrogen evolution reaction

Hydrogen evolution reaction (HER) performance of Ni3S2 electrocatalyst is associated with different morphologies and chemical compositions. In this work, nanosheets, nanorods and dendrite-like structure of Ni3S2 are synthesized and investigated as HER catalysts. Ni3S2Ni3S2 with interconnected nanosheets morphology exhibits the largest electrochemical active surface area, and thereby the lowest overpotential (288 mV vs. RHE) compared with Ni3S2 nanorods (314 mV vs. RHE) and dendrite-like Ni3S2 (303 mV vs. Ni(3)S(2)and thus interconnected Ni3S2@Ni(OH)(2) nanosheets have been obtained, demonstrating improved HER performance with decreased overpotential (237 mV vs. RHE) and superior stability. These results suggest that (i) the robust nanosheet structure of Ni3S2 can provide abundant space for contacting with electrolyte, which facilitates the mass transfer; and (ii) the formation of Ni3S2@Ni(OH)(2) heterostructure is beneficial for water dissociation in HER process, which brings about accelerated HER kinetics. (C) 2020 Elsevier B.V. All rights reserved.