Electrochemically exfoliated Ni-doped MoS2 nanosheets for highly efficient hydrogen evolution and Zn-H2O battery

Thanks to tunable physical and chemical properties,two-dimensional(2D)materials have received in-tensive interest,endowing their excellent electrocatalytic performances for applications in energy con-version.However,their catalytic activities are largely determined by poor adsorption energy and limited active edge sites.Herein,a one-step electrochemical exfoliation strategy was developed to fabricate 2D Ni-doped MoS2 nanosheets(Ni-EX-MoS2)with a lateral size of～500nm and thickness of～3.5nm.Prof-iting from high electrical conductivity and abundant exposing active sites,Ni-EX-MoS2 catalyst displayed an admirable performance for electrochemical hydrogen evolution reaction(HER)with a low overpoten-tial of 145 mV at 10mA/cm2 as well as a small Tafel slope of 89mV/dec in alkaline media,which are superior to those of the most reported MoS2-based electrocatalysts.The formed Ni species with tuning electronic structure played a crucial role as primary active center of Ni-EX-MoS2,as well as the forming stable 1T/2H phase MoS2 interface demonstrated a synergistic effect on electrocatalytic HER performance.Further,Ni-EX-MoS2 was employed as a cathode electrode for alkaline Zn-H2O battery,which displayed a high power density of 3.3 mW/cm2 with excellent stability.This work will provide a simple and effective guideline for design of electrochemically exfoliated transition metal-doped MoS2 nanosheets to inspire their practical applications in energy catalytic and storage.