A Cake-Style CoS2@MoS2/RGO Hybrid Catalyst for Efficient Hydrogen Evolution

A three-tiered cake-style composite is elaborately established, with the characteristic of a double-deck of MoS2 nanosheets and reduction of graphene oxide (RGO) sheets dotted with CoS2 nanoparticles (CoS2@MoS2/RGO). Because of the prominent synergistic effect of graphene acting as conductive support, MoS2 and CoS2 providing abundant catalytically active sites, and the cake-style structure promoting mechanical stability, the CoS2@MoS2/RGO exhibits a superior hydrogen evolution reaction activity with a small overpotential of 98 mV at cathodic current density of 10 mA cm(-2), and a small Tafel slope of 37.4 mV dec(-1), as well as excellent cycling stability. Density functional theory calculations reveal that the hydrogen adsorption free energy of CoS2@MoS2/RGO is close to zero.