Two-dimensional polarized MoTe 2 /GeS heterojunction with an intrinsic electric field for photocatalytic water-splitting.

The construction of van der Waals heterostructures based on 2D polarized materials is a unique technique to achieve enhanced photocatalytic performance. We have investigated the intrinsic electric field and photocatalytic properties of the MoTe 2 /GeS heterostructure via first-principles calculations. The results showed that a dipole-induced electric field induced by the GeS monolayer and an interface-induced electric field induced by the interface between the GeS monolayer and the MoTe 2 monolayer emerge in the 2D polarized MoTe 2 /GeS heterostructure. The dipole-induced electric field contributes mainly to the total intrinsic electric field. Moreover, the 2D polarized MoTe 2 /GeS heterostructure possesses many excellent and distinguished photocatalytic performance parameters, such as a direct semiconductor bandgap of 1.524 eV, a wide light spectrum ranging from the ultraviolet to near-infrared region with a high absorption coefficient (about 10 6 cm -1 ), a total intrinsic electric field, which reduces the probability of the recombination of photo-generated electron-hole pairs effectively, and a suitable band alignment for the water-splitting reaction. These indicate that the 2D polarized MoTe 2 /GeS van der Waals heterostructure is a potential novel high-efficient photocatalyst for water-splitting.