Developing highly efficient

durable

and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction (OER) is the pivotal for meeting the practical demand in water splitting. However

the current transition-metal electrocatalysts still suffer from low activity and durability on account of poor interfacial reaction kinetics. In this work

a facile solid-state synthesis strategy is developed to construct transition-metal sulfides heterostructures (denoted as MS

2

/NiS

2

M = Mo or W) for boosting OER electrocatalysis. As a result

MoS

2

/NiS

2

and WS

2

/NiS

2

show lower overpotentials of 300 mV and 320 mV to achieve the current density of 10 mA·cm

-2

and smaller Tafel slopes of 60 mV·dec

-1

and 83 mV·dec

-1

in 1 mol·L

-1

KOH

respectively

in comparison with the single MoS

2

WS

2

NiS

2

as well as even the benchmark RuO

2

. The experiments reveal that the designed heterostructures have strong electronic interactions and spontaneously develop a built-in electric field at th

e heterointerface with uneven charge distribution based on the difference of band structures

which promote interfacial charge transfer

improve absorptivity of OH

-

and modulate the energy level more comparable to the OER. Thus

the designed transition-metal sulfides heterostructures exhibit a remarkably high electrocatalytic activity for OER. This study provides a simple strategy to manipulate the heterostructure interface

via

an energy level engineering method for OER and can be extended to fabricate other heterostructures for various energy-related applications.