Abstract In this work, the Bi2W2O9/g-C3N4 type-II heterojunction system has been prepared for the first time by an incipient impregnation method. From the results, we have stated that the addition of low amounts of Bi2W2O9 (≤5 wt%) does not provide changes in the structural and textural properties of g-C3N4, but it improves substantially the photocatalytic performance under simulated solar irradiation. The best photoactive behavior was attained in the sample with 2 wt% of Bi2W2O9, providing a removal degree of the tetracycline antibiotic about 2.6 times higher than the pristine g-C3N4. This result can be explained due to the difference in the edge positions of the valence and conduction bands of both semiconductors, which provides an efficient separation of the photogenerated charge carriers. From the study of the photocatalytic activity under several conditions, it can be inferred that the Bi2W2O9 works as a sink for the photoexcited electrons of the g-C3N4 and provides the formation of hydroxyl radicals through sequential reactions involving the superoxide ions. Furthermore, a possible photocatalytic mechanism of tetracycline removal is discussed.

中文翻译：

---

在模拟太阳辐射下具有增强光催化性能的新型 II 型 Bi2W2O9/g-C3N4 异质结

摘要 本工作首次采用初始浸渍法制备了Bi2W2O9/g-C3N4 II型异质结体系。结果表明，添加少量 Bi2W2O9（≤ 5 wt%）不会改变 g-C3N4 的结构和结构特性，但可以显着提高模拟太阳辐射下的光催化性能。在含有 2 wt% Bi2W2O9 的样品中获得了最好的光敏行为，四环素抗生素的去除程度是原始 g-C3N4 的 2.6 倍。这一结果可以解释为两种半导体的价带和导带的边缘位置不同，这提供了光生电荷载流子的有效分离。从几种条件下的光催化活性研究可以推断，Bi2W2O9 充当 g-C3N4 光激发电子的汇，并通过涉及超氧离子的顺序反应形成羟基自由基。此外，还讨论了四环素去除的可能光催化机制。