In this paper, we investigate another strategy to enhance the charge transfer from the WSe 2 photoelectrode to the semiconductor-electrolyte interface: by forming a heterojunction between two semiconductors, an electrical field is generated which drives the excited electrons to the surface, thus enabling the reduction of the adsorbed protons to hydrogen molecules. This is done by depositing ammonium thiomolybdate (ATM) (mentioned above) films on top of the WSe 2 electrodes, thus creating a homogeneous heterojunction on the vdW planes along with the passivation of the edge states of WSe 2 .