Nickel@Nitrogen-Doped Carbon@MoS Nanosheets: An Efficient Electrocatalyst for Hydrogen Evolution Reaction.

Developing cheap, abundant, and easily available electrocatalysts to drive the hydrogen evolution reaction (HER) at small overpotentials is an urgent demand of hydrogen production from water splitting. Molybdenum disulfide (MoS ) based composites have emerged as competitive electrocatalysts for HER in recent years. Herein, nickel@nitrogen-doped carbon@MoS nanosheets (Ni@NC@MoS ) hybrid sub-microspheres are presented as HER catalyst. MoS nanosheets with expanded interlayer spacings are vertically grown on nickel@nitrogen-doped carbon (Ni@NC) substrate to form Ni@NC@MoS hierarchical sub-microspheres by a simple hydrothermal process. The formed Ni@NC@MoS composites display excellent electrocatalytic activity for HER with an onset overpotential of 18 mV, a low overpotential of 82 mV at 10 mA cm , a small Tafel slope of 47.5 mV dec , and high durability in 0.5 H SO solution. The outstanding HER performance of the Ni@NC@MoS catalyst can be ascribed to the synergistic effect of dense catalytic sites on MoS nanosheets with exposed edges and expanded interlayer spacings, and the rapid electron transfer from Ni@NC substrate to MoS nanosheets. The excellent Ni@NC@MoS electrocatalyst promises potential application in practical hydrogen production, and the strategy reported here can also be extended to grow MoS on other nitrogen-doped carbon encapsulated metal species for various applications.