One-pot synthesis of interfacially bonded Bi4O5Br2/Bi2S3 Z-scheme heterostructures with boosted photocatalysis towards dodecylbenzenesulfonate and real hotel laundry wastewater

The ubiquitous contamination of surfactants in wastewater has raised global concerns. Photocatalysis is deemed as a promising yet challenging approach for the decomposition of surfactant residues. Herein, a novel Z-scheme heterojunction of Bi4O5Br2/Bi2S3 with covalent S–O bonds was prepared via a facile one-pot hydrothermal and subsequent annealing process. The prepared optimal Bi4O5Br2/Bi2S3 composite exhibited remarkable photo-degradation activity towards the sodium dodecylbenzene sulfonate (SDBS). The Z-scheme reaction mechanism was proposed and validated by meticulous analysis of quenching tests, ESR spectroscopy and DFT calculations. Furthermore, the presence of chemical S–O linkages between Bi4O5Br2 and Bi2S3 was identified via FT-IR and XPS analyses, which served as a distinct bridge to modify the Z-scheme route for carrier transport. The Z-scheme heterostructure, in conjunction with chemical S–O bonds, synergistically enhanced the separation rate of electron-hole pairs and thus greatly boosted the photocatalytic activity. Additionally, the possible degradation pathways of SDBS were proposed by using HR-MS technology. Moreover, real hotel laundry wastewater could be efficiently disposed by the photocatalysis of the Bi4O5Br2/Bi2S3 with a decrease in the COD value from 428 to 74 mg/L, indicating that the fabricated Z-scheme heterojunction hold great promise for effectively removing refractory surfactant contaminants from aquatic environment.