Two-dimensional ultrathin BiOCl nanosheet/graphene heterojunction with enhanced photocatalytic activity

2D semiconductors and their heterostructures promise great potential in solar-driven photocatalysis owing to their unique properties that result from structural planar confinement. Herein, we fabricate the BiOCl nanosheet/graphene hybrid with 2D heterojunction through a hydrothermal and physical mixing two-step process. Studies on the heterostructure reveal the close interfacial contact between the BiOCl nanosheet and graphene through van der Waals interaction rather than chemical bonding. Compared with BiOCl-bulk/graphene hybrid, the BiOCl nanosheet/graphene hybrid showed superior photocatalytic activity towards dye decolorization and decomposition, featuring a remarkable enhancement of a 15-fold higher reaction rate. A series of characterizations reveal that the co-effect of the surface defect of the BiOCl nanosheet and graphene planar structure contributes to an extended light absorption range, better electrical conductivity and larger dye adsorption capacity. Furthermore, the unique van der Waals close contact between graphene and BiOCl promoted the fast and continuous consumption of photogenerated electrons, thereby effectively facilitating the separation of electron-hole pairs. This work underscores the key role of face-to-face heterojunction for the interfacial charge transfer process.