Molybdenum sulfide/graphene-carbon nanotube nanocomposite material for electrocatalytic applications in hydrogen evolution reactions

We report a three-dimensional hierarchical ternary hybrid composite of molybdenum disulfide (MoS2), reduced graphene oxide (GO), and carbon nanotubes (CNTs) prepared by a two-step process. Firstly, reduced GO-CNT composites with three-dimensional microstructuresare synthesized by hydrothermal treatment of an aqueous dispersion of GO and CNTs to form a composite structure via pi-pi interactions. Then, MoS2 nanoparticles are hydrothermally grown on the surfaces of the GO-CNT composite. This ternary composite shows superior electrocatalytic activity and stability in the hydrogen evolution reaction, with a low onset potential of only 35 mV, a Tafel slope of similar to 38 mV center dot decade(-1), and an apparent exchange current density of 74.25 mA center dot cm(-2). The superior hydrogen evolution activity stemmed from the synergistic effect of MoS2 with its electrocatalytically active edge-sites and excellent electrical coupling to the underlying graphene and CNT network.