Rose-like MoS2 nanostructures with a large interlayer spacing of ∼9.9 Å and exfoliated WS2 nanosheets supported on carbon nanotubes for hydrogen evolution reaction

In this study, we report a rose-like MoS2 and in-situ exfoliated WS2 nanoarchitecture supported on carbon nanotube networks for enhanced hydrogen evolution reaction. The interlayer expansion of MoS2 was carried out during in-situ exfoliation of WS2 nanosheets under a solvothermal process based on the ethanol-water mixture of sodium molybdate dihydrate and organosulfur chelating agent. Then, the MoS2-WS2 nanostructures are attached with carbon nanotubes (CNTs) to obtain the MoS2-WS2-CNTs nanoarchitectures where the interlayer expanded rose-like MoS2 nanostructures and the delaminated WS2 nanosheets are strongly associated with the electrically conductive carbon nanotubes, leading to a strong synergistic interaction among MoS2, WS2, and CNTs. Hence, the fabricated MoS2-WS2-CNTs nanoarchitectures delivered superior electrocatalytic activity towards the hydrogen evolution reaction (HER), yielding a current density of 10 mA cm(-2) at a low overpotential of similar to 212 mV with a Tafel slope of 50 mV dec(-1). Such superior HER electrocatalytic activity is due to the existence of abundant catalytic active sites in the both rose-like MoS2 nanostructures with large interlayer spacing of similar to 9.9 angstrom and exfoliated WS2 nanosheets with more edge sites, and facile electron transfer between conductive substrate and electrocatalytically active MoS2/WS2 materials through CNTs conducting channel. (C) 2019 Published by Elsevier Ltd.