Design of Lateral and Vertical Bi4o5i2/Biocl Heterojunctions with Different Charge Migration Pathway for Efficient Photoredox Activity

Two-dimensional (2D) lateral heterojunctions (LHs) and vertical heterojunctions (VHs) fabricated from 2D layered materials exhibit interesting properties due to their different interfacial structures and junctions. In this work, BiOCl and Bi4O5I2 were selected as model building blocks to construct BiOCl/Bi4O5I2 VHs and LHs. BiOCl/Bi4O5I2 LHs formed by chemical bonds (Bi-O-Bi) possess much stronger interfacial electric field (IEF) than BiOCl/Bi4O5I2 VHs formed based on van der Waals bonds (VDWb). The photogenerated charge migration pathway in the LHs was found to follow a Z-scheme model, while the VHs fits a type II model. As a result, the LHs show stronger photo-reduction and photo-oxidation activities than the pure BiOCl, pure Bi4O5I2 and the VHs, which is attributed to larger IEF, direct carrier channels and much stronger redox position in Z-scheme model. This study demonstrates a new approach to construct highly efficient facet-dependent 2D heterojunction photocatalysts.