A novel flower-like dual Z-scheme BiSI/Bi2WO6/g-C3N4 photocatalyst has excellent photocatalytic activity for the degradation of organic pollutants under visible light

Preparation of Z-scheme composite photocatalyst to degrade organic matter in water is the most popular research trend. However, due to the strict requirements of band edge energy level arrangement and interface contact, it is a great challenge to explore suitable photocatalytic materials to form Z-scheme photocatalytic system. In our work, a novel visible light driven double Z-scheme photocatalyst BiSI/Bi2WO6/g-C3N4 was successfully prepared by hydrothermal synthesis. The physicochemical properties of the materials were characterized by XRD, XPS, SEM, BET, UV–vis, PL, EIS and LC-MS. The photocatalytic degradation of tetracycline (TC), chlortetracycline (CTC) and rhodamine B (RhB) showed that BiSI/Bi2WO6/(20%) g-C3N4 had the best photocatalytic activity. The results free radical trap experiments demonstrate that h+ and O2− are the main free radicals in the photocatalytic process. Because of the heterojunction formed between BiSI, Bi2WO6 and g-C3N4, the electron conduction was accelerated, the photogenerated electrons and holes were separated effectively, and the photocatalytic performance of the composite was improved. Additionally, cycle test showed that BiSI/Bi2WO6/g-C3N4 hybrid material had stable degradation ability in the process of photodegradation. This unique heterojunction photocatalysis material has broad application prospects in the removal of organic pollutants and environmental treatment.