Janus XSSe/SiC (X = Mo, W) van der Waals heterostructures as promising water-splitting photocatalysts

The stability, electronic, and optical behaviours of XSSe/SiC (X = Mo, W) vdWs heterostructures have been investigated by first-principles calculations. The observed XSSe/SiC vdWs heterostructure is semiconductor with indirect bandgap, and it possesses type-II band alignment, which will promote the segregation of photogenerated carriers. In particular, the charge reallocation cause a large potential drop across XSSe/SiC vdWs heterostructure is 5.748 eV (MoSSe/SiC) and 5.849 eV (WSSe/SiC). Charge transfer demonstrates that the XSSe acts as an acceptor, while the SiC acts as a donor. Moreover, the tensile and compressive strain can regulate the band structures of the XSSe/SiC heterostructures from direct band gap to indirect band gap. Meanwhile, the vertical electric field can not change the band type of the XSSe/SiC heterostructures, but can regulate the band gap of the XSSe/SiC heterostructures. Importantly, the XSSe/SiC vdWs heterostructures have many strong peaks in the visible light region, resulting to efficient use of the solar energy. These attractive properties illustrate that the XSSe/SiC vdWs heterostructures are useful for attaining high-efficiency photocatalyst.