SiC/MoS2 layered heterostructures: Promising photocatalysts revealed by a first-principles study

Abstract

Van der Waals coupling is emerging as a powerful method to engineer atomically-thin semiconductor materials, which leads to unusual properties and plays an increasingly key role in catalysis and solar energy conversion. The electronic properties of these two-dimensional (2D) layers are critically important for their applications. Herein the electronic, interfacial and optical properties of 2D SiC/MoS2 van der Waals heterostructures have been investigated by using density functional theory with the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. Both the SiC/MoS2 heterostructure (SiC monolayer coupled with MoS2 monolayer) and SiC/BL-MoS2 heterostructure (SiC monolayer combined with MoS2 bilayer) demonstrate narrower band gaps than the two involved constituents, with a energy gap value of 1.46 eV and 1.36 eV, respectively, which mainly due to the formation of type-II heterojunctions for them and the sensitive electronic properties of SiC to lattice constant variations. Moreover, for the two vdW heterostructures, the electron transition mainly occurs between different constituents, which greatly facilitates effective separation for photogenerated charge carrier. The contradiction of the electrostatic potential and work functions difference in the nanocomposite is another key factor to improve the photocatalytic activity and stability. This work noth only reveals that the SiC/MoS2 and SiC/BL-MoS2 vdW heterostructure are both promising photocatalyst, but also provide an insight into the underlying mechanism in SiC/MoS2 semiconductor photocatalytic nanomaterials.