Constructing MoS2/g-C3N4 Heterojunction with Enhanced Oxygen Evolution Reaction Activity: A Theoretical Insight

•A systematic theoretical study of the OER electrocatalytic activity of MoS2/g -C3N4 heterojunction was performed.•The theoretical overpotential of the MoS2/g-C3N4 heterojunction was significantly reduced nearly 69% from 2.52 to 0.78 V compared with the pristine MoS2.•The outstanding OER activity of the MoS2/g-C3N4 heterojunction mainly originates from the electronic coupling between MoS2 and g-C3N4.