兰州大学机构库 >物理科学与技术学院
碳量子点的制备及其在光催化中的应用
Alternative TitlePreparation of carbon quantum dots and their application in photocatalysis
任海涛
Thesis Advisor李建功
2018-05-25
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword碳量子点 光致发光 SrTiO3 光催化 电荷分离
Abstract

碳量子点(carbon quantum dots, CQDs),作为一种新型零维碳纳米材料,由于其独特的光致发光(PL)性质、良好的光诱导电荷转移性质、高化学稳定性、良好亲水性、低毒性、良好生物相容性、高耐光性,这些优点使CQDs在光催化、药物转移、光电子器件、生物成像、离子检测等领域展现了巨大的应用前景,近年来引起了人们的广泛关注。

本文采用简单的化学氧化法。以活性炭为碳源,稀硝酸(HNO3)为氧化剂和腐蚀剂,制备了CQDs。利用XRD、TEM、SAED、Raman、FTIR、XPS等分析手段,对制备CQDs的结构进行了表征。结果表明,所制备的CQDs为非晶态、球形、完全分散无团聚、颗粒尺寸分布1.5-4.1 nm、平均颗粒尺寸2.7 nm,其表面丰富的含氧官能团赋予了CQDs良好的亲水性。同时,对制备CQDs的PL性质进行了研究,结果表明,CQDs具有上转换PL性质和稳定、pH敏感、激发波长依赖的下转换PL性质。

采用简单的化学浸渍法,将CQDs和SrTiO3纳米颗粒进行复合,制备出了一种新的光催化剂CQD/SrTiO3纳米复合材料。利用TEM、XRD、TEM、SAED、SEM mapping对CQD/SrTiO3纳米复合材料的结构进行了分析。对SrTiO3、CQD/SrTiO3分别作为光催化剂,在太阳光下降解罗丹明B(RhB)的光催化性能进行了评估。结果表明在相同条件下,CQD/SrTiO3纳米复合材料的光催化效率大约是SrTiO3 纳米颗粒的5.5倍,这说明CQD/SrTiO3纳米复合材料表现出了优良的光催化性能。CQD/SrTiO3纳米复合材料优良的光催化性,也许归因于光生电子从SrTiO3转移到CQDs,提高了SrTiO3 中电子(e-)和空穴(h+)的分离效率,从而增强了SrTiO3纳米颗粒的光催化性能。因此,制备的 CQDs在高效光催化剂的设计方面具有潜在的应用前景。这个工作也许为开发其他CQDs基纳米复合材料光催化剂打开了一扇门。

Other Abstract

Carbon quantum dots (CQDs) are a new type of zero-dimensional carbon nanomaterials and have been drawing much attention in recent years owning to their unique photoluminescence (PL), excellent electron transfer and reservoir properties, high chemical inertness, good hydrophilicity, low toxicity, good biocompatibility, environmental friendliness, and high photostability. CQDs have shown promising applications in photocatalysis, drug delivery, optoelectronic devices, bioimaging, and ion detection.

In this paper, we developed a facile chemical oxidation process to prepare CQDs by acidic oxidation of activated carbon with the most affordable oxidant and etching agent, nitric acid (HNO3). The structure of the CQDs were characterized by TEM, SAED, XRD, XPS, Raman, and FTIR. These results seggest that the as-prepared carbon quantum dots are completely disperse without any agglomeration, amorphous in structure, nearly spherical in shape, fine in size with an average particle size of 2.7 nm, and narrow in particle size distribution from 1.5 to 4.1 nm. The as-prepared CQDs possess oxygen-containing functional groups on their surface which endow them excellent hydrophilicity and exhibit stable, excitation-dependent, pH-sensitive and up-converted PL properties.

A novel CQD/SrTiO3 nanocomposite was prepared by combining the as-prepared CQDs with SrTiO3 nanoparticles through a simple impregnation process. The structure of the prepared CQD/SrTiO3 nanocomposite was analyzed by TEM, XRD, EDS, SEM mapping, and XPS. When the CQD/SrTiO3 nanocomposite and SrTiO3 nanoparticles were used as photocatalyst, respectively. Their photocatalytic performance was evaluated by degradation of Rhodamine B (RhB) under sunlight irradiation. Compared with pure SrTiO3, under the same conditions, the photocatalytic rate of the CQD/SrTiO3 photocatalyst is about 5.5 times higher than that of pure SrTiO3. This clearly indicates that the CQD/SrTiO3 photocatalyst shows an excellent photocatalytic performance in the photodegradation of RhB. The enhanced performance in the degradation of Rhodamine B may be attributed to the interfacial transfer of photogenerated electrons from SrTiO3 to CQDs, leading to effective electrons and holes separation in SrTiO3. So the as-prepared CQDs exhibit potential applications in high-efficiency photocatalyst design. This work may open a door to the development of new CQD-based photocatalytic nanocomposites.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229312
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
任海涛. 碳量子点的制备及其在光催化中的应用[D]. 兰州. 兰州大学,2018.
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