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

Abstract

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 ∼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 ∼9.9 Å 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.