A novel visible-light-induced double Z-scheme photocatalytic system: NH2-UiO-66/BiOBr/Bi2S3 for degradation of tetracycline hydrochloride and rhodamine B

The unique properties of MOFs make them the best candidates for catalytic and photocatalytic applications. In this research, the NH2-UiO-66 material was prepared by solvothermal method, and different content of NH2-UiO66 was added before the composite growth of Bi2S3 and BiOBr nanomaterials to obtain the NH2-UiO-66/BiOBr/ Bi2S3 ternary composite material. In order to investigate the relationship between the structure and properties of the catalyst, XRD, FT-IR, SEM, HRTEM, UV-vis DRS, XPS and other characterization technologies were used to analyze the structure, morphology, optical properties of the samples, showing that NH2-UiO-66/BiOBr/Bi2S3 have been successfully synthesized. Their photocatalytic performance was evaluated based on the photocatalytic degradation of tetracycline hydrochloride and rhodamine B under visible light. The results show that 2% NH2UiO-66/BiOBr/Bi2S3 has better photocatalytic activity than other materials. Moreover, NH2-UiO-66/BiOBr/Bi2S3 also demonstrated good photocatalytic reusability and stability. The formation of Bi2S3 and BiOBr heterojunctions and the introduction of NH2-UiO-66 with more active sites increase the carrier performance and separation efficiency. Then the valence band and conduction band values of the semiconductor material are calculated through the M-S curve, combined with the forbidden bandwidth deduced by UV-vis DRS and the experimental results of radical trapping, a double Z-type electron transfer mechanism suitable for this system is inferred. Finally, taking RhB as an example, the degradation path of dye pollutants was studied.

Automated summary

The NH2-UiO-66/BiOBr/Bi2S3 ternary composite material was successfully synthesized based on NH2-UiO-66, and its structure, morphology, and optical properties were characterized. The results showed that 2% NH2-UiO-66/BiOBr/Bi2S3 exhibited better photocatalytic activity and reusability. A double Z-type electron transfer mechanism suitable for this system was inferred by calculating the valence band and conduction band values of the semiconductor material and analyzing the experimental results. The degradation path of dye pollutants was also studied.