Probing the electronic structure and photocatalytic performance of g-SiC/MoSSe van der Waals heterostructures: A first-principle study

Highlights: • There is a weak built-in electric field (E_int) between two isolated layers. • Type Ⅱ band alignment of this vdWHs enhances separation of photogenerated carriers. • The photocatalytic properties of this vdWHs is modulated by different configurations. Trasition metal dichalcogenides with the Janus structures owe the intrinsic dipole, which can be used as photocatalysts in water splitting. In this work, the electronic properties and photocatalytic performances of g-SiC/MoSSe van der Waals heterostructures (vdWHs) have been investigated theoretically using the first principles calcualtions by PBE and hybrid HSE06 functional. The g-SiC/MoSSe vdWHs show the type Ⅱ (staggered) band gap alignment feature, implying that the redox reaction is carried out on two independent two-dimensional (2D) monolayers. The charge transfer from g-SiC to MoSSe monolayer leads to the generation of built-in electric field, which can effectively hinder photogenerated electron/hole (e^–/h⁺) from recombining, leading to tremendously improvement of the carrier mobility. Compared two isolated parts, g-SiC/MoSSe vdWHs exhibits relatively high absorption coefficients in the visible light region, exhibiting the striking advantages of high efficiency utilization of solar energy and high photocatalytic efficiency. Most remarkably, the photocatalytic properties can be modulated by the different configurations under varied pH conditions, providing a theoretical guidance for researchers to design the suitable photocatalytic water-splitting materials for different acid and alkali service conditions. In conclusion, this investigation offers new insights and fundamental understanding of g-SiC/MoSSe vdWHs as compelling photocatalysts for water splitting.