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首页> 外文期刊>Nanotechnology >Electron-transfer dependent photocatalytic hydrogen generation over cross-linked CdSe/TiO2 type-II heterostructure
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Electron-transfer dependent photocatalytic hydrogen generation over cross-linked CdSe/TiO2 type-II heterostructure

机译：电子转移依赖性光催化氢在交联Cdse / TiO2型异质结构上产生

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摘要

Developing type-II heterostructures with a spatial separation of photoexcited electrons and holes is a useful route to promote photocatalytic hydrogen generation. However, few investigations on the charge transfer process across the heterojunction have been carried out, which can allow us to uncover the reaction mechanism. Herein, CdSe quantum dots (QDs) and TiO2 nanocrystals were synthesized and combined in water yielding CdSe/TiO2 type II heterostructures. It was found that mercaptopropionic acid as bifunctional molecules could bind with CdSe and TiO2 to form a cross-linked morphology. The charge carrier dynamics of bare CdSe and CdSe/TiO2 were detected using femtosecond transient absorption spectroscopy. In the presence of TiO2, the average exciton lifetime of CdSe QDs was apparently decreased, owing to the electron transfer from photoexcited CdSe to TiO2. Particularly, the electron-transfer rate from small CdSe QDs (3.0 nm) was much faster than that from big CdSe QDs (4.2 nm). The improved photocatalytic hydrogen generation was observed for CdSe/TiO2 compared to bare CdSe QDs. The enhancement factor for small CdSe QDs was higher than that for big CdSe QDs, which was in good agreement with the electron-transfer rates. This result indicated that the electron transfer between CdSe and TiO2 played an important role in photocatalytic hydrogen generation on CdSe/TiO2 type-II heterostructure. Our study provides a fundamental guidance to construct efficient heterostructured photocatalysts by delicate control of the band alignment.
机译：显影II型异质结构，具有光透射电子和孔的空间分离是促进光催化氢气产生的有用途径。然而，已经进行了对杂交结的电荷转移过程的研究已经进行，这可以让我们揭示反应机制。在此，合成CDSE量子点（QDS）和TiO2纳米晶体在水中合成并合并在水中Cdse / TiO2型异质结构。结果发现，巯基丙酸作为双官能分子可与CdSe和TiO 2结合形成交联形态。使用Femtosecond瞬态吸收光谱检测裸CDSE和CDSE / TiO2的电荷载体动态。在TiO 2存在下，由于从光透明的Cdse至TiO 2的电子转移，CdSe QD的平均激子寿命显然降低。特别地，来自小CDSE QDS（3.0nm）的电子转移率比从大Cdse QDS（4.2nm）的速度快得多。与裸CDSEQDS相比，观察到CDSE / TiO 2的改进的光催化氢产生。小CDSE QDS的增强因子高于大CDSE QDS的增强因子，这与电子传输速率很好。该结果表明，CDSE和TiO2之间的电子转移在CDSE / TiO 2型异质结构上的光催化氢产生中起着重要作用。我们的研究提供了一种基本指导，通过精细控制带对准来构建有效的异质显影光催化剂。

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  • 来源
    《Nanotechnology》 |2017年第8期|共10页
  • 作者

    Chen Yubin; Chuang Chi-Hung; Qin Zhixiao; Shen Shaohua; Doane Tennyson; Burda Clemens;

  • 作者单位

    Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China;

    Case Western Reserve Univ Ctr Chem Dynam &

    Nanomat Res Dept Chem 10900 Euclid Ave Cleveland OH 44106 USA;

    Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China;

    Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China;

    Case Western Reserve Univ Ctr Chem Dynam &

    Nanomat Res Dept Chem 10900 Euclid Ave Cleveland OH 44106 USA;

    Case Western Reserve Univ Ctr Chem Dynam &

    Nanomat Res Dept Chem 10900 Euclid Ave Cleveland OH 44106 USA;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 特种结构材料;
  • 关键词

    CdSe/TiO2; type II heterostructure; quantum dots; dynamics; hydrogen generation;

    机译：CDSE / TiO2;II型异质结构;量子点;动态;氢气;

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