Facile synthesis of BiOBr/Bi2S3 topological heterojunction through acid vapor ion exchange and efficient application in environmental photocatalysis

Constructing tightly bound and highly dispersed heterointerfaces through epitaxial growth is a promising strategy for enhancing the photocatalytic performance of composite systems. In this study, a three-dimensional (3D) hierarchical flower-like BiOBr/Bi₂S₃ heterojunction was fabricated via an acid vapor ion exchange method. The highly matched lattice parameters facilitated the transformation of the BiOBr substrate into Bi₂S₃ through epitaxial growth, while the relatively mild reaction conditions at the gas-solid interface effectively preserved the initial morphological structure of the substrate. Benefiting from the expanded spectral response range, enhanced separation and migration efficiency of photogenerated carriers, and improved light utilization through complex scattering within the hierarchical structures, the BiOBr/Bi₂S₃ heterojunctions demonstrated exceptional photocatalytic activity in the degradation of Rhodamine B and Tetracycline Hydrochloride, as well as in the reduction of Cr(VI). This strategy not only provides a novel approach for the construction of topological heterojunctions but also holds significant potential as a universal methodology, offering broad prospects for both research and practical applications.