当前位置：
X-MOL 学术
›
J. Phys. Chem. C
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Mechanistic Insight into the Photocatalytic Working of Fluorinated Anatase {001} Nanosheets
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2017-11-16 00:00:00 , DOI: 10.1021/acs.jpcc.7b05586 Monika Kus 1 , Thomas Altantzis 2 , Stephan Vercauteren 3 , Ignacio Caretti 4 , Ortwin Leenaerts 3 , Kees Joost Batenburg 5, 6 , Myrjam Mertens 7 , Vera Meynen 1, 7 , Bart Partoens 3 , Sabine Van Doorslaer 4 , Sara Bals 2 , Pegie Cool 1
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2017-11-16 00:00:00 , DOI: 10.1021/acs.jpcc.7b05586 Monika Kus 1 , Thomas Altantzis 2 , Stephan Vercauteren 3 , Ignacio Caretti 4 , Ortwin Leenaerts 3 , Kees Joost Batenburg 5, 6 , Myrjam Mertens 7 , Vera Meynen 1, 7 , Bart Partoens 3 , Sabine Van Doorslaer 4 , Sara Bals 2 , Pegie Cool 1
Affiliation
|
Anatase nanosheets with exposed {001} facets have gained increasing interest for photocatalytic applications. To fully understand the structure-to-activity relation, combined experimental and computational methods have been exploited. Anatase nanosheets were prepared under hydrothermal conditions in the presence of fluorine ions. High resolution scanning transmission electron microscopy was used to fully characterize the synthesized material, confirming the TiO2 nanosheet morphology. Moreover, the surface structure and composition of a single nanosheet could be determined by annular bright-field scanning transmission electron microscopy (ABF-STEM) and STEM electron energy loss spectroscopy (STEM-EELS). The photocatalytic activity was tested for the decomposition of organic dyes rhodamine 6G and methyl orange and compared to a reference TiO2 anatase sample. The anatase nanosheets with exposed {001} facets revealed a significantly lower photocatalytic activity compared to the reference. In order to understand the mechanism for the catalytic performance, and to investigate the role of the presence of F–, light-induced electron paramagnetic resonance (EPR) experiments were performed. The EPR results are in agreement with TEM, proving the presence of Ti3+ species close to the surface of the sample and allowing the analysis of the photoinduced formation of paramagnetic species. Further, ab initio calculations of the anisotropic effective mass of electrons and electron holes in anatase show a very high effective mass of electrons in the [001] direction, having a negative impact on the mobility of electrons toward the {001} surface and thus the photocatalysis. Finally, motivated by the experimental results that indicate the presence of fluorine atoms at the surface, we performed ab initio calculations to determine the position of the band edges in anatase slabs with different terminations of the {001} surface. The presence of fluorine atoms near the surface is shown to strongly shift down the band edges, which indicates another reason why it can be expected that the prepared samples with a large amount of {001} surface, but with fluorine atoms near the surface, show only a low photocatalytic activity.
中文翻译：
机械洞察氟化的锐钛矿{001}纳米片的光催化工作。
具有暴露的{001}刻面的锐钛矿纳米片已经对光催化应用越来越感兴趣。为了充分理解结构与活性之间的关系，已经开发了组合的实验方法和计算方法。在水热条件下在氟离子的存在下制备了锐钛矿纳米片。使用高分辨率扫描透射电子显微镜对合成材料进行了充分表征，确定了TiO 2纳米片形态。此外，可以通过环形明场扫描透射电子显微镜（ABF-STEM）和STEM电子能量损失谱（STEM-EELS）确定单个纳米片的表面结构和组成。测试了有机染料若丹明6G和甲基橙分解的光催化活性，并与参考TiO 2锐钛矿样品进行了比较。与参考相比，具有暴露的{001}面的锐钛矿纳米片显示出显着较低的光催化活性。为了了解催化性能的机制，并探讨F的存在的作用-，进行了光致电子顺磁共振（EPR）实验。EPR结果与TEM一致，证明在样品表面附近存在Ti 3+物种，并可以分析光致顺磁性物种的形成。此外，锐钛矿中电子和空穴的各向异性有效质量的从头算算表明，在[001]方向上电子的有效质量非常高，这对电子向{001}表面的迁移率具有负面影响，因此对光催化。最后，受表明表面存在氟原子的实验结果的启发，我们从头开始计算以确定带{001}表面的不同末端的锐钛矿带中的带边缘的位置。已显示表面附近氟原子的存在强烈地使能带边缘向下移动，这表明了可以预期的是，制备的样品具有大量的{001}表面，但表面附近存在氟原子的另一个原因表明仅具有低的光催化活性。
更新日期：2017-11-17
中文翻译：
机械洞察氟化的锐钛矿{001}纳米片的光催化工作。
具有暴露的{001}刻面的锐钛矿纳米片已经对光催化应用越来越感兴趣。为了充分理解结构与活性之间的关系，已经开发了组合的实验方法和计算方法。在水热条件下在氟离子的存在下制备了锐钛矿纳米片。使用高分辨率扫描透射电子显微镜对合成材料进行了充分表征，确定了TiO 2纳米片形态。此外，可以通过环形明场扫描透射电子显微镜（ABF-STEM）和STEM电子能量损失谱（STEM-EELS）确定单个纳米片的表面结构和组成。测试了有机染料若丹明6G和甲基橙分解的光催化活性，并与参考TiO 2锐钛矿样品进行了比较。与参考相比，具有暴露的{001}面的锐钛矿纳米片显示出显着较低的光催化活性。为了了解催化性能的机制，并探讨F的存在的作用-，进行了光致电子顺磁共振（EPR）实验。EPR结果与TEM一致，证明在样品表面附近存在Ti 3+物种，并可以分析光致顺磁性物种的形成。此外，锐钛矿中电子和空穴的各向异性有效质量的从头算算表明，在[001]方向上电子的有效质量非常高，这对电子向{001}表面的迁移率具有负面影响，因此对光催化。最后，受表明表面存在氟原子的实验结果的启发，我们从头开始计算以确定带{001}表面的不同末端的锐钛矿带中的带边缘的位置。已显示表面附近氟原子的存在强烈地使能带边缘向下移动，这表明了可以预期的是，制备的样品具有大量的{001}表面，但表面附近存在氟原子的另一个原因表明仅具有低的光催化活性。
京公网安备 11010802027423号