Molybdenum Disulfide-Black Phosphorus Hybrid Nanosheets as a Superior Catalyst for Electrochemical Hydrogen Evolution.

Engineering electronic properties is a promising way to design nonprecious-metal or earth-abundant catalysts toward hydrogen evolution reaction (HER). Herein, we deposited catalytically active MoS flakes onto black phosphorus (BP) nanosheets to construct the MoS-BP interfaces. In this case, electrons flew from BP to MoS in MoS-BP nanosheets because of the higher Fermi level of BP than that of MoS. MoS-BP nanosheets exhibited remarkable HER performance with an overpotential of 85 mV at 10 mA cm. Due to the electron donation from BP to MoS, the exchange current density of MoS-BP reached 0.66 mA cm, which was 22 times higher than that of MoS. In addition, both the consecutive cyclic voltammetry and potentiostatic tests revealed the outstanding electrocatalytic stability of MoS-BP nanosheets. Our finding not only provides a superior HER catalyst, but also presents a straightforward strategy to design hybrid electrocatalysts.