Insight into the role of Ti3+ in photocatalytic performance of shuriken-shaped BiVO4/TiO2-x heterojunction
Insight into the role of Ti3+ in photocatalytic performance of shuriken-shaped BiVO4/TiO2-x heterojunction
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深入探讨 Ti3 在手里剑形 BiVO4/TiO2-x 异质结光催化性能中的作用
DOI：
10.1016/j.apcatb.2016.10.056
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Wang Chuanyi
中科院分区：
文献类型：
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作者：
Zhu Yunqing;Shah Muhammad Wajid;Wang Chuanyi
异质结被认为是提高光催化性能的有效途径，但其中匹配良好的能带对准是关键。在这项工作中，通过两步水热工艺设计具有Ti3+自掺杂的TiO2的电子结构，构建了shuriken形状的BiVO4/TiO2 − x异质结，以实现高的光催化性能。Ti3+的存在在TiO2的导带下产生缺陷能级，从而减小BiVO4和TiO2之间的界面能垒。Ti3+缺陷能级促进了电子从BiVO4向TiO2 − x导带的转移。在300 W氙灯（λ ≥ 420 nm）下，采用紫外截止滤光片对苯酚进行光催化降解实验，结果表明BiVO4/TiO2 − x异质结的光催化活性高于纯BiVO4和BiVO4/TiO2 − x的混合物。光催化性能的提高主要归因于BiVO4和TiO2 − x之间形成的异质结，通过比较光电流和时间分辨PL光谱测量，该异质结改善了作为载体的光生载流子的分离。此外，Ti3+自掺杂还使TiO2的禁带宽度变窄，可见光活性增强。TiO2 − x的空穴转移到BiVO4的价带，这进一步显著改善了光生载流子的分离。此外，由TiO 2-x引起的高表面积也有助于提高光催化效率。
Heterojunction is recognized as an effective approach to improve photocatalytic performance, but a well-matched energy band alignment is critical therein. In this work, the shuriken-shaped BiVO4/TiO2−xheterojunction is built by engineering the electronic structure of TiO2with Ti3+self-doping via a two-step hydrothermal process to achieve a high photocatalytic performance. The presence of Ti3+creates a defect energy level under the conduction band of TiO2, and thereby diminishes the interfacial energy barrier between BiVO4and TiO2. The Ti3+defect energy level promotes the electron transfer from BiVO4to conduction band of TiO2−x. The test of phenol degradation under 300 W Xenon lamp equipped with UV cut-off filter (λ ≥ 420 nm) demonstrates that BiVO4/TiO2−xheterojunction exhibits higher photocatalytic activity than its counter parts, pure BiVO4and the physic mixture of BiVO4and TiO2−x. The improved photocatalytic performance is mainly attributed to the heterojunction formed between BiVO4and TiO2−x, which improves the separation of photogenerated charge carriers as support by comparative photocurrent and time-resolved PL spectral measurements. In addition, Ti3+self-doping also narrows the bandgap of TiO2and enhances the visible-light activity of TiO2. The holes of TiO2−xtransfer to the valance band of BiVO4which further significantly improves the separation of photogenerated charge carriers, further. Additionally, the high surface area caused by TiO2-xalso contributes to the improved photocatalytic efficiency.