Highly Efficient Polarized GeS/MoSe₂ van der Waals Heterostructure for Water Splitting from Ultraviolet to Near-Infrared Light

A high-efficiency photocatalyst is critical for water splitting by solar light. Herein, via first principles calculations, the 2D polarized GeS/MoSe₂ van der Waals (vdW) heterostructure is proposed as an efficient water redox photocatalyst. The performance of GeS/MoSe₂ heterostructure is better than isolated materials, as the properties of GeS monolayer and MoSe₂ monolayer are complementary by forming vdW heterostructure. GeS/MoSe₂ heterostructure possesses suitable bandgap, dipole-induced internal electric field, and excellent solar absorption performance. The band alignments of GeS/MoSe₂ heterostructure are suitable compared with the redox potential of water. It is feasible to tune the optoelectronic properties and enhance photocatalytic activity of GeS/MoSe₂ heterostructure via strain engineering. Biaxial compressive strain range from −2% to −3% induces the direct bandgap characteristic in GeS/MoSe₂ heterostructure. The results suggest that 2D polarized GeS/MoSe₂ vdW heterostructure is a potential novel high-efficiency photocatalyst for water splitting under a wide range of spectra from ultraviolet to near infrared.