Photocatalytic degradation of antibiotics using a Li-C3N4/ZnO/BiOI: Insights on the electron transport pathways

Background: Environmental pollution demands the fabrication of suitable nano-photocatalyst that works under visible-light irradiation. The effective interfacial engineering is required for better separation of charges. Semiconductor heterostructure promotes the practical separation of electron-hole pairs and enhances the carrier separation efficiency, which has broad application prospects in photocatalytic degradation of Antibiotics. However, it remains a significant challenge to construct high-quality directly heterostructure effectively.Methods: In this work, a hierarchical ternary heterojunction (Li-C3N4/ZnO/BiOI) was facilely synthesized by employing an in-situ hydrothermal strategy with different ratios using Li-C3N4 as an anchor, in which the interaction at heterointerfaces was enhanced to improve the photocatalytic performance.Significant findings: The photocatalytic degradation experiment was carried out with Tetracycline (TC), and the effect of the molar ratio of Li-C3N4/ZnO to BiOI on the photocatalytic degradation performance was quantitatively investigated. Benefiting from the unique electronic structure of heterostructure, the results show that a degradation rate of 92.62% was achieved for 10 mg/L TC solution within 20 min. Moreover, Li-C3N4/ZnO/BiOI-5 offered high photocatalytic activity due to the type II and Z transport, resulting in a small forbidden band gap. The charge transport pathway improves the separation of photogenerated electron-hole pairs in Li-C3N4/ZnO/ BiOI. This study provides a promising avenue for rational design and application of ternary composites.