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首页> 外文期刊>Environmental Science & Technology >Improving Photocatalytic Water Treatment through Nanocrystal Engineering: Mesoporous Nanosheet-Assembled 3D BiOCI Hierarchical Nanostructures That Induce Unprecedented Large Vacancies
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Improving Photocatalytic Water Treatment through Nanocrystal Engineering: Mesoporous Nanosheet-Assembled 3D BiOCI Hierarchical Nanostructures That Induce Unprecedented Large Vacancies

机译：通过纳米晶体工程改善光催化水处理：介孔纳米片组装的3D BiOCI分层纳米结构，可导致空前的大空缺

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摘要

Vacancy control can significantly enhance the performance of photocatalytic semiconductors for water purification. However, little is known about the mechanisms and approaches that could generate stable large vacancies. Here, we report a new mechanism to induce vacancy formation on nanocrystals for enhanced photocatalytic activity: the introduction of mesopores. We synthesized two nanosheet-assembled hierarchical 3D BiOCl mesoporous nanostructures with similar morphology and exposed facets but different nanosheet thickness. Positron annihilation analysis detected unprecedentedly large V Bi) ‴)V O) ••)V Bi) ‴)V O) ••)V Bi) ‴) vacancy associates (as well as V Bi) ‴)V O) ••)V Bi) ‴)) on BiOCl assembled from 3–6 nm nanosheets but only V Bi) ‴)V O) ••)V Bi) ‴) vacancy associates on BiOCl assembled from thicker (10–20 nm) nanosheets. Comparison of vacancy properties with 2D ultrathin 2.7 nm nanosheets (with V Bi) ‴)V O) ••)V Bi) ‴) and V Bi) ‴)) indicates that nanosheet thinness alone cannot explain the formation of such large atom vacancies. On the basis of density functional theory computations of formation energy of isolated Bi vacancy, we show that mesopores facilitate the formation of large vacancies to counterbalance thermodynamic instability caused by incompletely coordinated Bi and O atoms along the mesopore perimeters. We corroborate that the extraordinarily large V Bi) ‴)V O) ••)V Bi) ‴)V O) ••)V Bi) ‴) vacancy associates facilitate photoexcitation of electrons and prevent the recombination of electron–hole pairs, which significantly enhances photocatalytic activity. This is demonstrated by the rapid mineralization of bisphenol A (10~(–5) M) with low photocatalyst loading (1 g L~(–1)), as well as enhanced bacterial disinfection. Improved electron–hole separation is also corroborated by enhanced photocatalytic reduction of nitrate.
机译：空缺控制可以显着提高光催化半导体净化水的性能。但是，对于可能产生稳定的大量空缺的机制和方法知之甚少。在这里，我们报告一个新的机制，以诱导纳米晶体上空位形成增强光催化活性：中孔的引入。我们合成了两个纳米片组装的分层3D BiOCl介孔纳米结构，它们具有相似的形态和暴露面，但纳米片的厚度不同。正电子an没分析检测到空前大的 V Bi）‴） VO）••） V Bi）‴） VO）••） V Bi）‴）空缺伴以及在3–6 nm纳米片上组装的BiOCl上的 V Bi）‴） VO）••） V Bi）‴）），但只有 V Bi）‴） VO ）••））V Bi）‴）由较厚的（10–20 nm）纳米片组装而成的BiOCl上的空位缔合体。与2D超薄2.7 nm纳米片（具有i Bi）的空位性能的比较（i）VO）••）i Bi））和i Bi）））表明纳米片的薄度单靠这一点无法解释如此大的原子空位的形成。根据孤立的Bi空位的形成能的密度泛函理论计算，我们表明中孔有利于大空位的形成，以抵消Bi和O原子沿中孔周界不完全配位引起的热力学不稳定性。我们证实，非常大的 V Bi）‴） VO）••） V Bi）‴） VO）••） V Bi）‴）空缺会促进光激发并阻止电子-空穴对的重组，从而显着增强光催化活性。双酚A（10〜（–5）M）的快速矿化和低光催化剂负载（1 g L〜（–1））以及增强的细菌消毒能力证明了这一点。增强的硝酸盐光催化还原作用也证实了改善的电子-空穴分离。

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  • 来源
    《Environmental Science & Technology》 |2018年第12期|6872-6880|共9页
  • 作者

    Sheng-qi Guo; Xiao-he Zhu; Hai-jun Zhang; Bing-chuan Gu; Wei Chen; Lu Liu; Pedro J. J. Alvarez;

  • 作者单位

    Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China,Tianjin Key Lab for Photoelectric Materials & Devices, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China;

    Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China;

    School of Physics and Materials Science, Anhui University, Hefei, Anhui 230039, China;

    State Key Laboratory of Particle Detection and Electronics, University of Science & Technology of China, Hefei, Anhui 230026, China;

    Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China;

    Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China;

    Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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