Developing highly efficient,durable,and non-noble electrocatalysts for the sluggish anodic oxygen evo-lution reaction (OER) is the pivotal for meeting the practical demand in water splitting.However,the cur-rent 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 MS2/NiS2,M =Mo or W) for boosting OER electro-catalysis.As a result,MoS2/NiS2 and WS2/NiS2 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 MoS2,WS2,NiS2,as well as even the bench-mark RuO2.The experiments reveal that the designed heterostructures have strong electronic interac-tions and spontaneously develop a built-in electric field at the 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.