Size-Dependent Photocatalytic Activity of Carbon Dots with Surface-State Determined Photoluminescence.
Size-Dependent Photocatalytic Activity of Carbon Dots with Surface-State Determined Photoluminescence.
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DOI：
10.1016/j.apcatb.2019.02.019
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
Yiqun Zhou;E. Zahran;Bruno A. Quiroga;J. Perez;Keenan J. Mintz;Zhili Peng;Piumi Y. Liyanage;R. R. P
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文献类型：
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作者：
Yiqun Zhou;E. Zahran;Bruno A. Quiroga;J. Perez;Keenan J. Mintz;Zhili Peng;Piumi Y. Liyanage;R. R. P
采用微波介导法制备了碳点，并用粒径排阻色谱法将其分离成三个不同粒径的组分。CD尺寸与光致发光（PL）发射波长没有相关性，表明PL机制不依赖于量子尺寸。紫外/可见吸收光谱和漫反射光谱表明，CDs的光吸收特性和带隙随颗粒尺寸的变化而变化。FTIR和XPS测量的结合揭示了每个馏分表面的组成。在模拟日光照射下，分别用三个CDs组分进行了光催化降解有机染料的研究。所制备的CDs的催化活性随着颗粒尺寸的减小而增加。在2nm的CDs下，罗丹明B （RhB）和亚甲基蓝（MB）在150 min内完全降解。清除剂研究表明，孔洞和超氧自由基是2纳米CDs光催化降解染料的主要物质。这些CDs在多循环降解有机染料方面表现出较高的稳定性。2纳米CDs在光催化降解对硝基苯酚（PNP）方面表现出良好的前景。这些结果首次证明了裸碳点在环境污染物降解中的应用。
Carbon dots (CDs) were synthesized by a microwave-mediated method and separated by size exclusion chromatography into three different size fractions. There was no correlation of CD size with photoluminescence (PL) emission wavelength, showing that the PL mechanism is not quantum-size dependent. UV/vis absorption and diffuse reflectance spectroscopies showed that the light absorption properties as well as the band gap of the CDs changed with the size of the particle. The combination of FTIR and XPS measurements revealed the composition on the surface of each fraction. The three CDs fractions were separately used in the photocatalytic degradation of organic dyes under simulated sunlight irradiation. The catalytic activity of the as-prepared CDs was found to increase as the size of the particles decreased. Complete degradation of both rhodamine B (RhB) and methylene blue (MB) was achieved in 150 min by the 2-nm CDs. The scavenger studies showed that the holes and superoxide radicals are the main species involved in the photocatalytic degradation of the dye by the 2-nm CDs. These CDs displayed high stability in the degradation of organic dyes for multiple cycles. The 2-nm CDs displayed promising photocatalytic degradation of p-nitrophenol (PNP). These results demonstrate for the first time the application of bare carbon dots in the degradation of environmental contaminants.