Highly active WO3@anatase-SiO2 aerogel for solar-light-driven phenanthrene degradation: Mechanism insight and toxicity assessment
Highly active WO3@anatase-SiO2 aerogel for solar-light-driven phenanthrene degradation: Mechanism insight and toxicity assessment
复制标题
用于太阳光驱动菲降解的高活性 WO3@锐钛矿-SiO2 气凝胶：机制洞察和毒性评估
DOI：
10.1016/j.watres.2019.06.017
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发表时间：
2019-10-01
期刊：
影响因子：
12.8
通讯作者：
Fu, Jie
中科院分区：
文献类型：
--
作者：
Cai, Zhengqing;Hao, Xiaodi;Fu, Jie
全球能源危机和水污染促使研究者开发高效、低能耗的水净化技术。在本研究中，合成了一种高活性WO3@TiO2-SiO2纳米复合材料，并将其用于模拟太阳光下光催化降解持久性有机污染物。负载2 wt% WO3, 800℃煅烧制备的最佳WO3@TiO2-SiO2光催化活性较高，降解菲的速率常数（k1）是商业TiO2 （P25）的7.1倍。WO3@TiO2-SiO2的极大比表面积（>400 m2/g）使其具有更大的污染物吸附性能和丰富的表面活性位点。锐钛矿与SiO2的异质结以及WO3的负载降低了TiO2的带隙能（Eg），将TiO2的利用光谱扩展到可见光区。Ti-O-Si带的形成表明，由于质子的吸收来补偿电荷，多余的电荷会引起Bronsted酸性。此外，光激发电子从锐钛矿的导带向WO3和相反方向的空穴迁移抑制了电子-空穴复合。基于实验分析和密度泛函理论（DFT）计算，提出了光催化降解菲的机理和途径，并通过定量构效关系（QSAR）分析评价了降解中间体的毒性。WO3@TiO2-SiO2也表现出良好的分离（沉降）性能和较高的稳定性。我们的工作有望为WO3， TiO2和SiO2基异质结的光催化机理提供新的见解，并为合理设计和合成环境应用的高效光催化剂提供新的思路。(C) 2019 Elsevier Ltd.版权所有。
The global energy crisis and water pollution drive the researchers to develop highly effective and less energy intensive water purification technologies. In this study, a highly active WO3@TiO2-SiO2 nanocomposite was synthesized and used for photocatalytic degradation of persistent organic pollutants under simulated solar light. The optimum WO3@TiO2-SiO2 prepared with 2 wt% WO3 loading and calcination at 800 degrees C exhibited higher photocatalytic activity, as the rate constant (k1) for phenanthrene degradation was similar to 7.1 times of that for the commercial TiO2 (P25). The extremely large specific surface area (>400 m2/g) of WO3@TiO2-SiO2 afforded it with enlarged pollutants adsorption performance and abundant active surface sites. The heterojunction of anatase with SiO2 as well as loading of WO3 decreased the band gap energy (Eg) of TiO2, which extended the utilization spectrum of TiO2 to visible region. Formation of Ti-O-Si band indicated the excess charges can cause Bronsted acidity due to the absorption of protons to compensate the charges. Moreover, the migration of photo-excited electrons from the conduction band of anatase to WO3 and holes in the opposite direction restrained the electron-hole recombination. The photocatalytic degradation mechanism and pathway for phenanthrene degradation were proposed based on experimental analysis and density functional theory (DFT) calculation, and the toxicities of the degradation intermediates were evaluated by quantitative structure-activity relationship (QSAR) analysis. WO3@TiO2-SiO2 also showed good separation (settling) performance and high stability. Our work is expected to offer new insight into the photocatalytic mechanism for WO3, TiO2 and SiO2 based heterojunctions, and rational design and synthesis of highly efficient photocatalysts for environmental application. (C) 2019 Elsevier Ltd. All rights reserved.