Two-dimensional Janus SnS/MoSi2N4 structure for high-efficiency photocatalytic splitting

Energy consumption and environmental pollution need us to explore new and sustainable energy sources. Photocatalytic water splitting for hydrogen production offers one of the most effective solutions to this problem. Identifying an advanced photocatalyst is essential to achieve high-efficiency photocatalytic water splitting. We observed that the SnS/MoSi2N4 van der Waals heterostructure (vdWH) is a viable candidate for photocatalytic water splitting using density functional theory (DFT). Our investigation has revealed that the SnS/MoSi2N4 vdWH exhibits type-II band alignment, which is highly advantageous for spatially separating photoexcited electron-hole pairs. Remarkably, this type-II band arrangement remains stable across different stacking forms of the vdWH. Meanwhile, SnS/MoSi2N4 vdWH exhibits high light absorption ability. After considering the Janus effect, we have ascertained that SnS/MoSi2N4 vdWH likely possesses appropriate band edge positions for facilitating water splitting. Moreover, we revealed that bandgap and light absorption of SnS/MoSi2N4 vdWH could be further improved by applying the strain while SnS/MoSi2N4 vdWH still maintains the appropriate band edge positions. The results suggest that SnS/MoSi2N4 vdWH is an ideal photocatalyst for water splitting.