Synthesis of One-Dimensional CdS@TiO2 Core-Shell Nanocomposites Photocatalyst for Selective Redox: The Dual Role of TiO2 Shell
Synthesis of One-Dimensional CdS@TiO2 Core-Shell Nanocomposites Photocatalyst for Selective Redox: The Dual Role of TiO2 Shell
复制标题
用于选择性氧化还原的一维 CdS@TiO2 核壳纳米复合材料光催化剂的合成：TiO2 壳的双重作用
DOI：
10.1021/am302074p
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发表时间：
2012-11-01
影响因子：
9.5
通讯作者：
Xu, Yi-Jun
中科院分区：
文献类型：
--
作者：
Liu, Siqi;Zhang, Nan;Xu, Yi-Jun
采用两步溶剂热法合成了一维CdS @ TiO 2核壳纳米复合材料。采用X射线衍射（XRD）、紫外-可见光（UV-vis）漫反射光谱（DRS）、场发射扫描电子显微镜（FESEM）、光致发光光谱（PL）和电子自旋共振（ESR）等技术对一维CdS @ TiO 2核壳纳米复合材料（CdS @ TiO 2 CSNs）的结构和性能进行了表征。结果表明，在CdS纳米线的基底上包覆TiO 2形成了一维核壳结构。在温和的条件下，通过选择性氧化醇类生成醛类化合物，考察了所制备的ID CdS@TiO2 CSNs的可见光催化活性.与裸CdS纳米线相比，一维CdS@TiO2 CSNs的转化率和产率都有明显的提高，这是由于在可见光照射下，一维CdS@TiO2 CSNs的光生载流子寿命延长所致.此外，还公开了来自CdS核心的光生空穴可以被TiO 2壳卡住，这一点通过受控自由基清除剂实验和ID CdS @ TiO 2 CSN上重金属离子Cr（VI）的有效选择性还原得到了证明，因此，一维CdS@光催化氧化醇的反应机理在可见光照射下，TiO 2 CSNs与一维CdS纳米线上的CSNs有明显的不同。希望我们的工作不仅能为各种特定的一维核壳纳米结构的制备提供有用的信息，而且也为这种一维核壳半导体作为可见光催化剂在有前途的选择性转化领域开辟了一条新的途径。
One-dimensional (1D) CdS@TiO2 core-shell nanocomposites (CSNs) have been successfully synthesized via a two-step solvothermal method. The structure and properties of ID CdS@TiO2 core-shell nanocomposites (CdS@TiO2 CSNs) have been characterized by a series of techniques, including X-ray diffraction (XRD), ultraviolet-visible-light (UV-vis) diffuse reflectance spectra (DRS), field-emission scanning electron microscopy (FESEM), photoluminescence spectra (PL), and electron spin resonance (ESR) spectroscopy. The results demonstrate that ID core-shell structure is formed by coating TiO2 onto the substrate of CdS nanowires (NWs). The visible-light-driven photocatalytic activities of the as-prepared ID CdS@TiO2 CSNs are evaluated by selective oxidation of alcohols to aldehydes under mild conditions. Compared to bare CdS NWs, an obvious enhancement of both conversion and yield is achieved over 1D CdS@TiO2 CSNs, which is ascribed to the prolonged lifetime of photogenerated charge carriers over 1D CdS@TiO2 CSNs under visible-light irradiation. Furthermore, it is disclosed that the photogenerated holes from CdS core can be stuck by the TiO2 shell, as evidenced by controlled radical scavenger experiments and efficiently selective reduction of heavy-metal ions, Cr(VI), over ID CdS@TiO2 CSNs, which consequently leads to the fact that the reaction mechanism of photocatalytic oxidation of alcohols over 1D CdS@TiO2 CSNs is apparently different from that over 1D CdS NWs under visible-light irradiation. It is hoped that our work could not only offer useful information on the fabrication of various specific 1D core-shell nanostructures, but also open a new doorway of such 1D core-shell semiconductors as visible-light photocatalysts in the promising field of selective transformations.