A novel Z-scheme CdS/Bi4O5Br2 heterostructure with mechanism analysis: Enhanced photocatalytic performance

Highlights: • Z-scheme CdS/Bi₄O₅Br₂ heterostructure was prepared by mixed solvent thermal method. • Addition of CdS enhanced the range and intensity of CdS/Bi₄O₅Br₂ to visible light. • CdS/Bi₄O₅Br₂ boosted the separation efficiency of photoinduced electron hole pairs. • CdS/Bi₄O₅Br₂ exhibited optimal activity and stability for CIP degradation. -- Abstract: The novel Z-scheme CdS/Bi₄O₅Br₂ heterostructure was successfully synthesized by a simple mixed-solvent thermal method. It proved that the Z-scheme CdS/Bi₄O₅Br₂ heterojunction was constructed by XRD, SEM, TEM and XPS. The synthesis of CdS nanospheres on ultra-thin Bi₄O₅Br₂ nanosheets to form a heterojunction interface was beneficial to the dispersion and transfer of the photogenerated electron–hole pairs, which was demonstrated by PL, i-t and EIS. UV-Vis diffuse reflectance spectra attested CdS/Bi₄O₅Br₂ heterojunction enhanced utilization of visible light. The Z-scheme 0.5-CdS/Bi₄O₅Br₂ heterojunction exhibited the highest photocatalytic performance for degradation process of CIP and TC than that of pure CdS and Bi₄O₅Br₂. In addition, recycling tests declared that the Z-scheme 0.5-CdS/Bi₄O₅Br₂ heterojunction compared with single CdS had higher stability and durability, attributing to effectively alleviating photocorrosion of CdS. It could be seen from the trapping agent experiment that superoxide free radicals and hydroxyl free radicals were the main active substances. The possible photocatalytic mechanism of the Z-scheme 0.5-CdS/Bi₄O₅Br₂ heterojunction under visible light irradiation was proposed.