Design and Photocatalytic Performance of the New Direct Z-Scheme Heterojunction XSe₂/Sih (X = Zr, Sn) for Overall Water Splitting

The development of high-performance direct-Z Scheme heterojunctions as photocatalysts is the focus of current research, and it is also an effective way to improve the performance of photocatalysts. Based on this, we use density functional theory (DFT) to predict two-dimensional (2D) XSe₂/SiH (X = Zr, Sn) van der Waals (vdW) heterojunction as a potential direct Z-scheme heterojunction photocatalyst. The results indicate that both heterojunctions exhibit a typical Type-II band edge arrangement. Furthermore, the small band gap and built-in electric field of the heterojunctions facilitate electronic transitions between the valence band (VB) and conduction band (CB), thereby increasing the probability of interlayer electron–hole (e⁻-h⁺) recombination within the heterojunction. This process is beneficial for the formation of direct-Z Scheme heterojunctions. In addition, the XSe₂/SiH (X = Zr, Sn) heterojunction exhibits remarkable photogenerated electron and hole driving forces, along with exceptional light-trapping capabilities. Therefore, XSe₂/SiH (X = Zr, Sn) heterojunction is a potential new photocatalyst.