Sulfur-doped 2D/3D carbon nitride-based van der Waals homojunction with superior photocatalytic hydrogen evolution and wastewater purification

The weaker van der Waals force between layers inhibits the interlayer electron migration, which greatly limiting the enhancement of the photocatalytic activity over graphitic carbon nitride (g-C₃N₄). Herein, the metal-free sulfur-doped 2D/3D van der Waals (vdW) homojunction (2D/3D CNSCN) that containing 2D sulfur-doped g-C₃N₄ nanosheets (CNS) and 3D g-C₃N₄ flower-like hierarchical structure (CN) was fabricated. Thanks to the cooperative effect of 2D-3D structural and good compatibility between CNS and CN, an in situ formed 2D/3D vdW homojunction served as the driving force for promoting charge carrier separation and transfer. The optimal photocatalytic H₂ evolution of 2D/3D CNSCN reached up to 2196 μmol h^?1g^?1, which was 4.1 and 3.2 times higher than that of CN and CNS, respectively. 10 mg of the 2D/3D CNSCN photocatalyst was able to totally remove of rhodamine B (RhB) solution in less than 80 min under the visible light. This study provides new opportunities to construct novel 2D/3D mixed-dimensional vdW homojunction, and broad interest in vdW homojunction research for the applications in energy conversion and environmental protection field.