The application of photocatalysts in water governance has attracted extensive attention, and past research efforts often focused on single pollutant removal. Simultaneous removal of multiple pollutants from wastewater by a single processing unit is highly desirable, realistic, and challenging. The use of band-matched semiconductors to form heterojunctions is an important way to achieve this technology. In this work, we have designed a Bi₂WO₆/g-C₃N₄ heterojunction via an in-situ growth method. The in-suit XPS was used to verify the electron transfer pathway which conforms to the S-scheme mechanism. Under visible light irradiation, the removal rates of Cr(VI) and TC are 97.7% and 96.0% respectively. In addition to the excellent photocatalytic performance, the catalyst showed a high degree of stability during the five cycles. The formation mechanism of S-scheme heterojunction is discussed based on DFT calculation and physicochemical characterization. Liquid chromatography-mass spectrometry (LC-MS) and Quantitative Structure-Activity Relationship (QSAR) were used to analyze and predict the degradation pathways, intermediates, and toxicity. The efficient performance of the photocatalyst is attributed to the more efficient photogenerated charge transfer efficiency brought about by the formation of the built-in electric field, and the improvement of the photogenerated carrier recombination rate to provide more reactive sites with a large specific surface area. We provide a practicable strategy for the efficient treatment of inorganic and organic co-pollutants in environmental water by constructing an S-scheme heterojunction photocatalyst.

中文翻译：

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可见光驱动的 S 型 Bi2WO6/石墨氮化碳异质结，用于高效同时去除 TC 和 Cr（VI）


光催化剂在水治理中的应用引起了广泛关注，以往的研究工作往往集中在单一污染物的去除上。通过单个处理装置同时去除废水中的多种污染物是非常可取的、现实的和具有挑战性的。使用带匹配半导体形成异质结是实现这项技术的重要途径。在这项工作中，我们通过原位生长方法设计了一种 Bi₂WO₆/g-C₃N₄ 异质结。套装内 XPS 用于验证符合 S 方案机制的电子转移途径。在可见光照射下，Cr（VI） 和 TC 的去除率分别为 97.7% 和 96.0%。除了优异的光催化性能外，该催化剂在五次循环中也表现出高度的稳定性。基于 DFT 计算和物理化学表征讨论了 S 型异质结的形成机理。采用液相色谱-质谱 （LC-MS） 和定量构效关系 （QSAR） 分析和预测降解途径、中间体和毒性。光催化剂的高效性能归因于内置电场的形成带来的更高效的光生电荷转移效率，以及光生载流子复合速率的提高，以提供更多具有大比表面积的反应位点。我们通过构建 S 型异质结光催化剂，为有效处理环境水中无机和有机共污染物提供了一种可行的策略。