High efficiency in overall water-splitting via Co-doping heterointerface-rich NiS2/MoS2 nanosheets electrocatalysts

Abstract

Designing heterostructure in electrocatalysts can enhance the reaction kinetics of overall water splitting by exposing more active sites and promoting the electron transfer. Mo-based and Ni-based sulfides, which have respectively shown excellent catalytic activity in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), can remedy the shortcomings of single half-reaction by synergistic effect. Herein, we realized the in-situ growth of Co-doped NiS2/MoS2 nanosheet on CFP (Co-NiS2/MoS2) using a two-step hydrothermal method. The Co-NiS2/MoS2 nanosheets exhibit superior activity for durable HER and OER, obviously superior to those of the single-structure catalysts. Moreover, the cell voltage is only 1.63 V at 10 mA cm−2 for overall water splitting. The density functional theory simulation results show the hydrogen adsorption energy in Co-NiS2/MoS2 system is closer to zero than others, further suggesting heterostructure can reduce energy barrier of water splitting.