Construction of heterojunction and design of its architecture are effective strategies to improve the catalytic performance of photocatalyst. Herein, BiOBr/Bi₂O₄ p-n heterojunction was fabricated by a co-precipitation method, in which two-dimensional (2D) BiOBr nanosheets sheathed well on the surface of quasi-one-dimensional (1D) Bi₂O₄ submicrorods, forming a three-dimensional (3D) hierarchical structure. Such structural feature can not only enhance the utilization of incident photons through multi-reflection within the hierarchical structure but also raise the specific surface areas to supply more surface-active sites to participate in photocatalytic reaction. More importantly, BiOBr/Bi₂O₄ p-n junction could accelerate the interfacial electron-hole pairs transfer and separation via the built-in electric field, extending the lifetime of charge carriers. Thus, as-prepared BiOBr/Bi₂O₄ heterojunctions exhibit superior visible light catalytic activity for the photodegradation of 4-chlorophenol (4-CP). The catalytic activity of optimal junction is 2.03-fold as high as that of pristine Bi₂O₄. The trapping experiments demonstrate that hole (h⁺) and superoxide radical (•O₂⁻) are the major active species during the catalytic photodegradation process of 4-CP. This work presents a unique tactic for the construction of high-performance Bi₂O₄-based heterojunction for the removal of organic pollutants.

异质结的构建及其结构的设计是提高光催化剂催化性能的有效策略。在此，BiOBr/Bi ₂ O ₄ pn 异质结是通过共沉淀法制备的，其中二维（2D）BiOBr 纳米片很好地包裹在准一维（1D）Bi ₂ O ₄亚微米棒的表面，形成三维 (3D) 层次结构。这种结构特征不仅可以通过分级结构内的多次反射来提高入射光子的利用率，还可以提高比表面积以提供更多的表面活性位点参与光催化反应。更重要的是，BiOBr/Bi ₂ O ₄pn结可以通过内置电场加速界面电子-空穴对的转移和分离，延长电荷载流子的寿命。因此，所制备的 BiOBr/Bi ₂ O ₄异质结对 4-氯苯酚 (4-CP) 的光降解表现出优异的可见光催化活性。最佳结的催化活性是原始Bi ₂ O ₄催化活性的2.03倍。捕获实验表明空穴(h ⁺ ) 和超氧自由基(•O ₂ ^- ) 是4-CP 催化光降解过程中的主要活性物质。这项工作为构建高性能 Bi ₂ O提供了独特的策略_4-基异质结用于去除有机污染物。