In-situ formation and integration of graphene into MoS2 interlayer spacing: expansion of interlayer spacing for superior hydrogen evolution reaction in acidic and alkaline electrolyte

For the commercial-scale of hydrogen production from water-splitting, developing earth-abundant and competitive price catalysts is highly demanding, but it is challenging to replace the noble metal-based state-of-the-art catalysts. Herein, we report MoS 2 @graphene (MoS 2 @Gr) heterostructures materials as a promising hydrogen evolution reaction (HER) electrocatalyst, which is synthesized via in-situ formation and integration of graphene into the interlayer spacing of MoS 2 , thereby exposing the HER active edge sites via widening of the interlayer spacing. Compared to the pristine MoS 2 , the MoS 2 @Gr exhibits a superior HER activity having an overpotential of 120 mV vs. RHE to drive the current density of 10 mA cm −2 with a small Tafel slope of 72 mV dec −1 in 0.5 M H 2 SO 4 solution. In addition, the MoS 2 @Gr catalyst requires only an overpotential of 170 mV vs. RHE in 1 M KOH electrolyte to drive the HER current densities of 10 mA cm −2 with a smaller Tafel slope of 51 mV dec −1 . Moreover, the MoS 2 @Gr catalyst presents long-term durability against HER in both acidic and alkaline electrolytes. Graphical abstract