First-Principles Study on Direct Z-Scheme WSi2N4/C2N van der Waals Heterostructure Photocatalyst

Abstract

Two-dimensional van der Waals heterostructures (vdWHs) have garnered significant attention owing to their promising applications in photocatalytic water splitting. Developing efficient photocatalysts with low recombination rate of photogenerated carriers and superb optical property remains a stern challenge. Here, the electronic and photocatalytic performances of WSi₂N₄/C₂N vdWH were examined applying first-principles approach. Research results demonstrate that WSi₂N₄/C₂N vdWH has sufficient thermodynamic stability. WSi₂N₄/C₂N vdWH possesses a staggered band arrangement with direct HSE06 band gap of 1.501 eV. Built-in electric field directing from WSi₂N₄ to C₂N can facilitate photogenerated carrier transfer along direct Z-shaped path, which is advantageous for effective electron-hole separations. Importantly, WSi₂N₄/C₂N vdWH shows appropriate band edge positions that satisfy criteria for efficient photocatalyst and displays a more outstanding light absorption capacity than WSi₂N₄ monolayer and C₂N monolayer. This present study offers theoretical support for designing and preparing WSi₂N₄/C₂N vdWH.