GQD驱动的纳米碳材料的自组装及电化学性能

发布时间：2018-10-30 17:55

【摘要】：石墨烯、碳纳米管等纳米碳材料因其优异的电化学性能,在电化学催化和电化学储能领域展现出广阔的应用前景。然而石墨烯、碳纳米管等纳米碳材料易聚集、表面无活性官能团,难与其它材料进行复合,这成为阻碍纳米碳材料实际应用的瓶颈问题。针对这个问题,本论文设计采用石墨烯量子点(GQD)修饰纳米碳材料,既可以提高纳米碳材料的分散性能,又能在不破坏纳米碳材料共轭结构的基础上,为纳米碳材料表面带来能与金属离子、聚苯胺等结合的位点,达到控制复合材料微结构的目的。另外,作为一种新型的纳米碳材料,GQD不损害石墨烯、碳纳米管等纳米碳材料的导电性和电化学稳定性。因此采用GQD修饰纳米碳材料,是实现纳米碳复合材料可控制备的新思路和新方法。主要内容如下:(1)采用石墨烯量子点(GQD)功能化修饰多壁碳纳米管(MWNT),制备分散均匀的多壁碳纳米管/石墨烯量子点(MWNT/GQD)水溶液,然后利用GQD表面的羧基官能团均匀的吸附Ag+、Ni2+,在碱性条件下水热反应生成Ni(OH)_2,同时实现GQD表面的含氧官能团和Ag+的还原,获得MWNT/GQD/Ag/Ni(OH)_2纳米复合材料。电化学检测结果表明:该复合材料修饰的玻碳电极可以有效地催化葡萄糖的无酶电化学氧化。研究发现随着Ag和Ni含量的改变,复合物的电催化性能也随之改变,其中Ag和Ni含量占MWNT质量80wt%时MWNT/GQD/Ag/Ni(OH)_2纳米复合材料电化学性能最好。在5.0×10-7mol/L~2×10-4 mol/L范围内该纳米复合材料修饰的玻碳电极可以有效检测葡萄糖,检测限为2×10-7mol/L。相对于抗坏血酸、双氧水、硝苯地平、多巴胺该修饰电极对葡萄糖有唯一的电化学识别作用。(2)分别以热还原法、混酸剥离碳纤维法和化学氧化法制备了还原氧化石墨烯(rGO)、石墨烯量子点(GQD)和聚苯胺(PANI)。进一步以GQD为连接体,以rGO和PANI为原料,采用溶液共混法制备rGO/GQD/PANI三元复合粉体材料,并用恒流充放电实验研究复合材料的电容性能。通过研究反应物的质量比对rGO/GQD/PANI纳米复合材料的结构及超电容性能的影响可知,当石墨烯与聚苯胺质量比为1:1时得到的rGO/GQD/PANI纳米复合材料具有最优的电容性能,比电容可达到324 F/g,相对于纯组分PANI的比电容194 F/g有了大幅提高;1000次充放电循环后,rGO/GQD/PANI纳米复合材料比电容损失只有19%,而纯PANI的比电容损失高达68%。(3)以rGO/GQD与PANI分散液为组装前体,以π-π作用和静电力为驱动力,采用层层自组装的方法制备了结构均匀致密的rGO/GQD/PANI层层自组装膜。电化学检测结果表明,rGO/GQD/PANI层层自组装膜修饰的氧化铟锡(ITO)电极,可以有效的催化中性水溶液中双氧水的电化学还原。时间-电流实验证明rGO/GQD/PANI层层自组装膜/ITO电极可以有效检测水溶液中双氧水的浓度,其检测线性范围为5.0×10-7 mol/L~4×10-5mol/L,线性相关系数为0.99。相同条件下,该电极对抗坏血酸、葡萄糖、硝苯地平、多巴胺等无电化学响应,说明rGO/GQD/PANI层层自组装膜/ITO电极是良好的双氧水电化学识别和检测器件。
[Abstract]:Graphene, carbon nanotubes and other nano-carbon materials exhibit a wide application prospect in the field of electrochemical catalysis and electrochemical energy storage due to their excellent electrochemical properties. However, the nano-carbon materials such as graphene and carbon nano-tubes are easy to collect and have no active functional groups on the surface and are difficult to compound with other materials, thus becoming the bottleneck problem of the practical application of the nano-carbon material. According to the problem, the graphene quantum dot (GQD) modified nano-carbon material is designed, so that the dispersion property of the nano-carbon material can be improved, The bonding sites of polyaniline and the like are used to achieve the purpose of controlling the microstructure of the composite material. In addition, as a novel nano-carbon material, GQD does not damage the conductivity and electrochemical stability of nano-carbon materials such as graphene and carbon nanotubes. Therefore, using GQD modified nano-carbon material is a new way to realize the controllable preparation of nano-carbon composite material. The main contents are as follows: (1) a graphene quantum dot (GQD) functionalized modified multi-wall carbon nano tube (MWNT) is adopted to prepare a dispersed uniform multi-wall carbon nano tube/ graphene quantum dot (MWNT/ GQD) aqueous solution, and then the Ag + and the Ag + are uniformly adsorbed on the surface of the GQD surface, An MWNT/ GQD/ Ag/ Ni (OH) _ 2 nanocomposite was obtained by hydrothermal reaction under alkaline condition to produce Ni (OH) _ 2, simultaneous reduction of oxygen-containing functional groups and Ag + on the surface of GQD. Electrochemical detection results show that the modified glassy carbon electrode can effectively catalyze the enzyme-free electrochemical oxidation of glucose. The results show that the electrochemical performance of MWNT/ GQD/ Ag/ Ni (OH) _ 2 nanocomposite is the best when the content of Ag and Ni accounts for 80wt% of MWNT. The glassy carbon electrode modified by the nano composite material can effectively detect glucose in the range of 5. 0-10-7mol/ L-2-10-4 mol/ L, and the detection limit is 2-10-7mol/ L. The modified electrode has a unique electrochemical recognition effect on glucose relative to ascorbic acid, hydrogen peroxide, NiNi3 and dopamine. (2) Reduction of graphene oxide (rGO), graphene quantum dots (GQD) and PANI (PANI) were prepared by thermal reduction method, mixed acid stripping carbon fiber method and chemical oxidation method respectively. RGO/ GQD/ PANI ternary composite powder material was prepared with rGO and PANI as raw materials with GQD as the linker, and the capacitance properties of the composites were investigated by constant flow charge and discharge experiments. When the mass ratio of graphene to polyaniline is 1: 1, the rGO/ GQD/ PANI nano composite material obtained by the mass ratio of graphene to polyaniline is 1: 1 has the optimal capacitance performance, and the specific capacitance can reach 324F/ g, Compared with the pure component PANI, the specific capacitance 194F/ g is greatly improved; after 1000 charge and discharge cycles, the rGO/ GQD/ PANI nano composite material is only 19% higher than the capacitance loss, and the specific capacitance loss of the pure PANI is 68% higher than that of the pure PANI. (3) The rGO/ GQD/ PANI layer self-assembled film with uniform structure was prepared by layer-by-layer self-assembly method with rGO/ GQD and PANI dispersion as the pre-assembly. Electrochemical detection results show that rGO/ GQD/ PANI layer self-assembled membrane modified tin oxide (ITO) electrode can effectively catalyze the electrochemical reduction of hydrogen peroxide in neutral aqueous solution. The time-current experiment proves that the rGO/ GQD/ PANI layer self-assembled film/ ITO electrode can effectively detect the concentration of hydrogen peroxide in the aqueous solution, and the detection linear range is 5. 0-10-7 mol/ L-4, 10-5mol/ L, and the linear correlation coefficient is 0. 99. Under the same conditions, the electrode has no electrochemical response to ascorbic acid, glucose, NiNip, dopamine and the like, and indicates that the rGO/ GQD/ PANI layer-by-layer self-assembled membrane/ ITO electrode is a good electrochemical recognition and detection device for hydrogen peroxide.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71;TB383.1

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