石墨烯及其分散液的制备与应用研究

发布时间：2018-05-07 23:20

本文选题：氧化石墨 + 石墨烯　；参考：《北京化工大学》2016年博士论文

【摘要】：作为21世纪最有前途的材料之一,石墨烯具有非常稳定的结构、高的载流子迁移率、高导电和导热性、超强的机械性能、高的比表面积和很好的光学透过率等优异的物理化学性质,在电子、航天、光学、能源、环境、新材料等众多传统和新兴领域展现出广阔的应用前景。虽然石墨烯具有很多优异的物理化学性能,但是当大量单层石墨烯聚集在一起时,很容易因为片层间的强π-π堆叠力和强范德华力作用而发生不可逆团聚,所以石墨烯很难在溶剂中稳定分散,这极大地限制了其应用。此外,石墨烯的规模化制备还存在很多困难,探索大规模、低成本、高质量、尺寸均一可控地制备石墨烯的方法对于石墨烯的应用具有非常重要的意义。针对以上问题,本论文主要研究内容如下：1.红铝还原制备RGO和RGO/Al(OH)3复合材料。首次使用红铝作为氧化石墨(Graphite Oxide, GO)的还原剂和Al(OH)3的前驱体,通过选择不同的后处理方法,可以选择性地获得还原氧化石墨烯(Reduced Graphene Oxide, RGO)和RGO/A1(OH)3的复合材料。使用XRD、FT-IR、 Raman、XPS、HRTEM、SAED对产物的结构和形貌进行了分析。研究发现红铝移除了GO表面大量的含氧官能团,RGO的C/O为9.0,电导率为99 S/cm,较GO提高了5个数量级。研究结果还表明：A1(OH)3以平均直径为200 nm的圆薄片形式均匀地吸附于RGO片表面或填充于RGO片层之间而形成均一的RGO/Al(OH)3复合材料。最后讨论了可能的脱氧和Al(OH)3形成的机理。该方法不仅提供了一种新的还原氧化石墨烯的还原剂,同时也提供了一条制备RGO/Al(OH)3复合材料的新路径。2.超重力法红铝还原制备石墨烯。将快速和高效的红铝还原反应和超重力旋转床(Rotating packed bed, RPB)相结合开发出一条简单且有效的可规模化制备RGO的方法。在该工作中,使用超重力旋转床作为反应装置,红铝作为还原剂,采用盐酸洗涤的后处理工艺来规模化制备RGO。将超重力旋转床制备得到的石墨烯(RPB-RGO)与机械搅拌装置(Stirred Tank Reactor, STR)得到的产品(STR-RGO)进行了对比,并使用XRD、 FT-IR、TGA、Raman、SEM和CV (Cyclic Voltammetry, CV)对得到的产物的结构、形貌和电学性能进行了表征。研究发现RPB中的还原反应较STR装置中的更彻底。CV研究结果表明当扫描速率从10 mV/s到100mV/s变化时,RPB-RGO制备的电极的比电容从1 8.3 F/g增加到43 F/g,而STR-RGO的比电容从12.7 F/g增加到28.5 F/g。该方法提供了一条有效且可规模制备RGO的方法。3.边缘氧化石墨烯及其水相分散液的制备与应用研究。本研究通过降低KMnO4的用量和减少氧化时间制备得到边缘被含氧基团功能化而碳基底平面sp2杂化结构未被破坏的边缘氧化石墨(Edge-oxidized graphite, EOG)。使用胆酸钠(sodium cholate, SC)作为稳定剂,对EOG进行超声制备得到浓度为0.59 mg/ml的边缘氧化石墨烯(edge-oxidized graphene nanosheets, EOGNs)的水相分散液,该分散液在室温下放置六个月而不发生沉降。将该稳定的EOGNs水相分散液用于制备透明导电薄膜,其透过率为87.6%(550 nm)时的电导率为26.4 kΩ/□。此外,研究发现EOG较GO可分散的溶剂更多,扩大了其应用范围。该方法使得规模制备低缺陷石墨烯分散液成为可能。4.石墨烯及其有机相分散液的制备与应用研究。将浓HN03预处理的石墨(NG)作为起始原料,聚乙烯吡咯烷酮(PVP)作为稳定剂,草酸和NaCl作为插层剂,采用水热插层剥离NG的PVP+草酸+NaCl的水溶液,洗涤之后在待测有机试剂中超声、离心得到稳定的有机相石墨烯分散液。优化了水热剥离工艺,发现水热温度为240℃,水热时间为12 h时,剥离效果最优。采用真空抽滤法,将乙醇相石墨烯分散液用于制备石墨烯透明导电薄膜,其透过率为81.2%(550 nm)时的电导率为28.0 kΩ%。最后讨论了可能的水热剥离NG的机理。该方法为石墨烯应用于石墨烯基复合材料提供了很好的前驱体材料。
[Abstract]:As one of the most promising materials of the twenty-first Century, graphene has a very stable structure, high carrier mobility, high conductivity and thermal conductivity, super mechanical properties, high specific surface area and excellent optical transmittance, and other excellent physical and chemical properties, such as electronic, spaceflight, optics, energy, environment, new materials and many other traditional and emerging leaders. Although graphene has many excellent physical and chemical properties, graphene has many excellent physical and chemical properties, but when a large number of monolayer graphene is gathered together, it is very easy to have irreversible reunion because of the strong pion pion stacking force and Jon Vander Ed Ley action between the layers. So graphene is difficult to disperse in the solvent. This is very limited. In addition, there are still many difficulties in the large-scale preparation of graphene. It is very important for the application of graphene to be prepared on a large scale, low cost, high quality, uniform size and controllable preparation of graphene. In this paper, the main contents of this paper are as follows: 1. RGO and RGO/Al (OH) 3 composites are prepared by the reduction of red aluminum. Material. Using red aluminum as a precursor of Graphite Oxide (GO) and Al (OH) 3 for the first time, by selecting different post-processing methods, the compound of reductive graphene oxide (Reduced Graphene Oxide, RGO) and RGO/A1 (OH) 3 can be selectively obtained. The morphology was analyzed. It was found that the red aluminum moved in addition to a large number of oxygen functional groups on the GO surface, and the C/O of RGO was 9 and the conductivity was 99 S/cm, and 5 orders of magnitude higher than that of GO. The results also showed that A1 (OH) 3 was evenly adsorbed on the surface of RGO slices or filled between RGO lamellae with an average diameter of 200 nm. L (OH) 3 composite. Finally, the possible mechanism of deoxidization and the formation of Al (OH) 3 is discussed. This method not only provides a new reducing agent for the reduction of graphene oxide, but also provides a new route for preparing RGO/Al (OH) 3 Composite by.2. supergravity method of red aluminum reduction and preparation of graphene. A simple and effective method for preparing RGO by Rotating packed bed (RPB) is developed. In this work, a super gravity rotating bed is used as a reaction device, and red aluminum is used as a reducing agent, and the post-processing technology of hydrochloric acid washing is used to prepare RGO. to prepare the graphene prepared by a super gravity rotating bed. RPB-RGO) compared with the product (STR-RGO) obtained by the mechanical agitation device (Stirred Tank Reactor, STR), and used XRD, FT-IR, TGA, Raman, SEM and CV to characterize the structure, morphology and electrical properties of the obtained products. It is shown that when the scanning rate changes from 10 mV/s to 100mV/s, the specific capacitance of the electrodes prepared by RPB-RGO increases from 18.3 F/g to 43 F/g, while the specific capacitance of STR-RGO increases from 12.7 F/g to 28.5 F/g.. The method provides an effective and scalable method for preparing RGO, the preparation and application of.3. marginal graphene oxide and its aqueous dispersions. By reducing the amount of KMnO4 and reducing the oxidation time, the marginal oxide graphite (Edge-oxidized graphite, EOG), which was not destroyed by the carbon base plane SP2 hybrid structure, was obtained by the functionalization of the oxygen group on the edge. Using sodium cholate (sodium cholate, SC) as a stabilizer, the concentration of 0.59 mg/ml was obtained by ultrasonic preparation of EOG. The aqueous dispersions associated with edge-oxidized graphene nanosheets (EOGNs) are placed at room temperature for six months without settling. The stable EOGNs aqueous dispersions are used to prepare transparent conductive films. The conductivity of the transparent conductive film is 26.4 K OMEGA / h when the transmission rate is 87.6% (550 nm). Furthermore, it is found that EOG is more dispersible than GO. The preparation and application of.4. graphite (NG) as starting material, polyvinylpyrrolidone (PVP) as a stabilizer, oxalic acid and NaCl as intercalating agent, and using water as intercalating agent, are used as a intercalating agent. The aqueous solution of NG PVP+ oxalic acid +NaCl was stripped by thermal intercalation. After washing, the stable organic phase graphene dispersions were obtained by centrifugation in the organic reagent after washing. The hydrothermal stripping process was optimized. The optimum stripping effect was found when the hydrothermal temperature was 240 C and the hydrothermal time was 12 h. The vacuum extraction method was used to make the ethanol phase graphene dispersions used in the preparation. The conductivities of the transparent conductive graphene films with the conductivity of 81.2% (550 nm) are 28 K Omega%. Finally, the possible mechanism of the possible hydrothermal dissection of NG is discussed. This method provides a good precursor material for graphene based composite materials used in graphene.

【学位授予单位】：北京化工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ127.11

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