掺杂型石墨烯量子点的可控制备及其光致发光与电催化研究
发布时间：2018-11-19 10:56
【摘要】：石墨烯量子点(Graphene Quantum Dots,GQDs)具有显著的量子限域效应、边界效应和良好的生物兼容性等特点,在荧光标记、微纳传感器、靶向医疗、生物示踪及电催化领域具有巨大的应用前景。掺杂能有效地调节石墨烯量子点的晶体和电子结构,从而改变其光致发光和电催化等性能。目前石墨烯量子点的产业化应用仍然存在诸多难题,如可控制备、改性和低成本量产等。本文以碳纤维和石墨粉为原料,采用强氧化刻蚀割裂法制备石墨烯量子点,并提出一种能显著提高石墨烯基材料掺杂量的通用制备方法—阶跃分步掺杂法。成功制备出掺杂型石墨烯量子点及其纳米复合物,应用于光致发光和电催化。本文主要开展以下工作:1、石墨烯量子点的可控制备。分别以碳纤维(Carbon Fibers)和石墨粉(Graphite Powders)为原材料,采用强氧化刻蚀割裂法制备石墨烯量子点。实验结果显示,两种石墨烯量子点的粒径均在6 nm以下,荧光量子产率分别为2%、1%(硫酸奎宁为参比),表现出显著的荧光依赖激发波长变化的性质。2、石墨烯量子点的掺杂。先制备氟掺杂石墨烯量子点F-GQDs(Fluorine-doped GQDs),使GQDs内部缺陷浓度增加,再进行氨气高温掺氮处理制备氮原子比例可控的N-GQDs。实验结果显示,当氟化剂与石墨烯量子点的质量比为5:1,热处理温度为700℃时,F-GQDs的氟原子掺杂量为23%,N-GQDs的氮原子掺杂量高达4.25%,对于未氟化直接进行氮掺杂的N-GQDs样品,氮原子掺杂量仅为1.6%,说明采用掺氟预处理的阶跃分步掺杂法能显著提高氮原子的掺杂量。3、掺杂型石墨烯量子点的性能。(1)光致发光性能:N-GQDs的荧光光谱较未掺杂GQDs蓝移20 nm,量子产率提高1.5倍,紫外灯照射下的发光颜色由黄色变为黄绿色,N-GQDs的荧光强度随添加Fe~(3+)浓度的升高而显著降低;(2)电催化性能:N-GQDs 700在0.1MKOH碱性条件下的半波电位和极限电流密度分别为0.76 V、3.69mAcm~(-2)(催化剂载量600μg cm~(-2)),经过2500圈循环后,分别衰减2.4%、2.7%;采用一步溶剂热法合成四氧化三钴与氮掺杂石墨烯量子点纳米复合物(Co_3O_4@N-GQDs)。Co_3O_4@N-GQDs 450在0.1M KOH碱性条件下的半波电位和极限电流密度分别为0.77 V、5.48 mA cm~(-2)(催化剂载量600μg cm~(-2)),经过2500圈循环后,半波电位衰减0.7%,极限电流密度略有降低,对比N-GQDs 700催化剂其催化活性增强,稳定性提高。本文为掺杂型石墨烯量子点在光致发光应用于生物医疗领域提供了思路,开发出低成本、高效的非金属氧还原催化剂,为掺杂型石墨烯量子点在能源材料领域的应用提供理论依据和技术支持。
[Abstract]:Graphene Quantum Dots (Graphene Quantum Dots,GQDs) have remarkable quantum limiting effect, boundary effect and good biological compatibility, in fluorescence labeling, microsensor, targeted medical treatment, etc. Biological tracer and electrocatalysis have great application prospects. Doping can effectively regulate the crystal and electronic structure of graphene quantum dots, thus changing their photoluminescence and electrocatalytic properties. At present, there are still many problems in the industrial application of graphene quantum dots, such as controllable preparation, modification and low cost production. In this paper, graphene quantum dots were prepared from carbon fiber and graphite powder by strong oxidation etching, and a step doping method, which can significantly increase the doping amount of graphene based materials, was proposed. The doped graphene quantum dots and their nanocomposites were successfully prepared and used in photoluminescence and electrocatalysis. The main work of this paper is as follows: 1. Controllable preparation of graphene quantum dots. Graphene quantum dots were prepared with carbon fiber (Carbon Fibers) and graphitic powder (Graphite Powders) as raw materials. The experimental results show that the particle size of the two graphene QDs is less than 6 nm, and the fluorescence quantum yields are 2% (quinine sulfate as reference), respectively, showing a remarkable fluorescence dependence on the excitation wavelength. 2. Doping of graphene quantum dots. Fluorine-doped graphene quantum dots (F-GQDs) were prepared first (Fluorine-doped GQDs), increased the internal defect concentration of GQDs, and then N-GQDswith controllable nitrogen atom ratio were prepared by ammonia nitrogen treatment at high temperature. The experimental results show that when the mass ratio of fluorides to graphene quantum dots is 5: 1 and the heat treatment temperature is 700 鈩，
本文编号：2342089
[Abstract]:Graphene Quantum Dots (Graphene Quantum Dots,GQDs) have remarkable quantum limiting effect, boundary effect and good biological compatibility, in fluorescence labeling, microsensor, targeted medical treatment, etc. Biological tracer and electrocatalysis have great application prospects. Doping can effectively regulate the crystal and electronic structure of graphene quantum dots, thus changing their photoluminescence and electrocatalytic properties. At present, there are still many problems in the industrial application of graphene quantum dots, such as controllable preparation, modification and low cost production. In this paper, graphene quantum dots were prepared from carbon fiber and graphite powder by strong oxidation etching, and a step doping method, which can significantly increase the doping amount of graphene based materials, was proposed. The doped graphene quantum dots and their nanocomposites were successfully prepared and used in photoluminescence and electrocatalysis. The main work of this paper is as follows: 1. Controllable preparation of graphene quantum dots. Graphene quantum dots were prepared with carbon fiber (Carbon Fibers) and graphitic powder (Graphite Powders) as raw materials. The experimental results show that the particle size of the two graphene QDs is less than 6 nm, and the fluorescence quantum yields are 2% (quinine sulfate as reference), respectively, showing a remarkable fluorescence dependence on the excitation wavelength. 2. Doping of graphene quantum dots. Fluorine-doped graphene quantum dots (F-GQDs) were prepared first (Fluorine-doped GQDs), increased the internal defect concentration of GQDs, and then N-GQDswith controllable nitrogen atom ratio were prepared by ammonia nitrogen treatment at high temperature. The experimental results show that when the mass ratio of fluorides to graphene quantum dots is 5: 1 and the heat treatment temperature is 700 鈩，
本文编号：2342089
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