Carbon quantum dots embedded with mesoporous hematite nanospheres as efficient visible light-active photocatalysts
Carbon quantum dots embedded with mesoporous hematite nanospheres as efficient visible light-active photocatalysts
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DOI：
10.1039/c2jm16931b
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发表时间：
2012-04
影响因子：
--
通讯作者：
B. Yu;S. Kwak
中科院分区：
文献类型：
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作者：
B. Yu;S. Kwak
采用溶剂热法在水溶液中制备了碳量子点（CQDs）和介孔赤铁矿（α-Fe 2 O3）复合光催化剂。具有高比表面积和多孔框架的介孔结构α-Fe 2 O3簇是光催化剂设计中的重要考虑因素，因为这种结构增强了光子的吸收并促进了有机污染物的分解。更重要的是，该催化剂中的CQDs在可见光照射下的光催化活性的提高中起着关键作用。采用X射线光电子能谱、傅里叶变换红外光谱、X射线衍射、能量色散谱、场发射扫描电子显微镜、透射电子显微镜、动态光散射法、紫外-可见光谱等技术对纳米复合材料进行了表征。结果证实了CQD/介孔α-Fe 2 O3杂化团簇的形成，其具有均匀的尺寸（约700 nm）、三维球形形貌、大的内表面积（高达187 m2 g−1）和虫洞状介孔结构。此外，这些新型复合催化剂在可见光区显示出连续的吸收带。CQD嵌入的介孔α-Fe 2 O3的光催化研究表明，在可见光照射下，对水介质中的有机化合物的降解具有优异的光催化效率（在三个循环后高达97%的容量保持率）。在此基础上，对体系的物化性质与光催化性能之间的关系进行了描述和讨论。
Carbon quantum dots (CQDs) and mesoporous hematite (α-Fe2O3) complex photocatalysts were successfully prepared using a facile solvent-thermal process in an aqueous solution. Mesostructured α-Fe2O3 clusters with a high surface area and a porous framework were an important consideration in the design of the photocatalysts because such structures enhance the absorption of photons and promote the decomposition of organic pollutants. More significantly, the CQDs in this catalyst play a pivotal role in improving the photocatalytic activity under visible light irradiation. The nanocomposites were characterized using X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, energy-dispersive spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, dynamic light scattering methods, ultraviolet-visible spectroscopy, and other techniques. The results confirmed the formation of CQD/mesoporous α-Fe2O3 hybrid clusters with a uniform size (about 700 nm), three-dimensional spherical morphologies, a large internal surface area (up to 187 m2 g−1), and a wormhole-like mesopore structure. Moreover, these novel composite catalysts displayed a continuous absorption band in the visible region. Photocatalytic studies of the CQD-embedded mesoporous α-Fe2O3 showed excellent photocatalytic efficiency (up to 97% capacity retention after three cycles) toward the degradation of organic compounds in aqueous media under visible light irradiation. The relationship between the physicochemical properties and the photocatalytic performance in our system is described and discussed on the basis of the results.