【作者】 杜海军；

【导师】 叶建山；

【作者基本信息】 华南理工大学 ， 应用化学， 2010， 博士

【摘要】 近年来随着纳米科学技术的发展,特别是随着荧光碳纳米颗粒、富勒烯、碳纳米管、以及石墨烯等纳米结构相继被发现,碳素纳米材料科学研究得到了广泛的关注。石墨烯是碳原子紧密堆积成单层二维蜂窝状晶格结构的一种碳质新材料,是构建零维富勒烯、一维碳纳米管、三维石墨等其它碳质材料的基本单元,具有许多优异而独特的物理、化学和机械性能,在微纳电子器件、光电子器件、新型复合材料以及传感材料等方面有着广泛的应用前景,基于石墨烯的相关研究也成为目前电化学领域的热点研究领域之一。荧光碳纳米颗粒由于具有无毒、化学惰性以及良好的生物相容性的特点,在生物和医药领域具有重要的潜在应用价值,所以研究它的制备方法具有非常重要的意义。本论文以石墨烯功能材料的制备为基础,研究了其在电化学传感器中的应用,同时,用电化学方法快速的制备了荧光碳纳米颗粒。其具体内容归纳如下:1)运用氧化还原法制备了石墨烯功能材料,利用扫描电子显微镜、原子力显微镜、红外光谱和拉曼光谱进行表征,分析了石墨烯的结构及其形态,为石墨烯功能材料在电化学传感器及电催化方面的应用提供了物质保证。2)在水和离子液体的辅助下,利用一种简单、快速、绿色的电化学方法,一步即可制备石墨烯。扫描电子显微镜和原子力显微镜证实了二维石墨烯纳米薄膜具有单层结构,薄膜的边缘发生卷曲。拉曼光谱推断其含有一定的缺陷。红外光谱表明,石墨烯不含有含氧官能团,如:羧基、羟基、羰基等。此外,利用微分脉冲伏安法对多巴胺（DA）、抗坏血酸（AA）和尿酸（UA）进行了测定,结果表明该石墨烯对三种分子的氧化反应具有优良催化活性。利用石墨烯对pH的敏感性质,研发了基于石墨烯的pH传感器。石墨烯/Au修饰电极对pH变化有很大响应,在pH 3.0～11.0区间内呈良好线性关系,灵敏度为53.88 mV/pH。3)首次开发出一种容易的一步法在乙醇溶液中电化学刻蚀石墨合成发蓝绿色荧光的碳纳米颗粒的方法。利用透射显微镜、红外光谱和拉曼光谱进行了表征,分析了荧光碳纳米材料的结构以及形态。其发光机制是碳纳米颗粒表面的缺陷使碳纳米颗粒表面产生了能量势阱,导致了碳纳米颗粒的可见光发射。这些单分散荧光碳纳米颗粒具有无毒、化学惰性和良好的生物相容性,在生物医药领域具有重要的应用价值。4)利用石墨烯研制了测定芦丁的电化学传感器,芦丁可以在石墨烯修饰电极表面有效地富集,并且对芦丁的氧化具有很好的电催化作用。芦丁在电极表面的电化学过程是吸附控制,伴随着两个电子和两个质子的转移。芦丁的氧化峰电流与其浓度在1×10⁷ M到1×10?5 M范围内呈良好的线性关系,相关系数为0.996,其检出限是2.1×10?8 M。电极容易再生,且具有良好的抗干扰能力。利用该方法成功地对药片中芦丁的含量进行了测定。5)利用石墨烯研制了直接测定对苯二酚和邻苯二酚的电化学传感器。在醋酸缓冲溶液（pH 4.5）中,对苯二酚和邻苯二酚的氧化峰电位距离约112 mV;同时,其阳极氧化电流很大,这使得它适合于同时测定这些化合物。在优化的条件下,利用差分脉冲伏安法,在5×10^-5 M邻苯二酚的存在的条件下,响应电流与对苯二酚的浓度在1×10^-6 M到5×10^-5 M之间呈良好的线性关系,相关系数为0.991,检测限为1.5×10-8 M。同样在5×10^-5 M对苯二酚的存在下,响应电流与邻苯二酚的浓度在1×10^-6 M到5×10^-5 M与之间呈良好的线性关系,相关系数为0.994,检测限为1.0×10-8 M。石墨烯修饰电极表现出了良好的稳定性、高的灵敏度和良好的选择性,并应用于模拟水样品中对对苯二酚和邻苯二酚的同时测定。更多还原

【Abstract】 With the rapid development of nanoscience and nanotechnology, carbon related nanostructures have attracted extensive interests, especially after the discovery of fluorescent carbon nanoparticles, carbon nanotube, fulleren and graphene. Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional （2D） honeycomb lattice, which can be considered as a basic building block for other carbon-based materials including 0D fullerenes, 1D carbon nanotubes and 3D graphite. These carbon-based materials possess outstanding and unique physical, chemical and mechanical properties, and have been widely applied in the design of devices of micro-nano-electronics, optoelectronics, novel composite materials and sensing materials. At present, the researches related to graphene have become the one of hottest research point in the field of electrochemistry. Compared with the conventional quantum dot based on sulphides, selenides, or tellurides of zinc and cadmium, fluorescent carbon nanoparticles （CNPs） are more promising for the application in biology labelling and life science due to their excellent properties, such as low cytotoxicity, biocompatibility, and chemically inert. Therefore, it shows a great significance in studying the method for preparing the fluorescent carbon nanoparticles.In this thesis, studies on the method to prepare graphene and the electrochemical properties of graphene and graphene-based composite materials were carried out. Meanwhile, the fluorescent carbon nanoparticles were prepared by electrochemistry method. The main points of this thesis are briefly summarized as follows:1) The method of reducing oxided-graphene was employed to prepare graphene. Scanning electron microscopy （SEM）, atomic force microscopy （AFM）, infrared spectroscopy （FT-IR）, Raman spectroscopy and other characterization techniques were employed to characterize the graphene. The graphene provide a potential application in preparing and designing new electrochemical sensors and electrocatalysis material.2) Highly efficient and large-scale synthesis of graphene from graphite through electrolytic exfoliation in the ionic liquid electrolyte was introduced. SEM and AFM confirmed the existence of monolayer graphene sheets and stacks containing a few graphene sheets. Raman spectroscopy demonstrated that the as-prepared graphene sheets have low content defect. FT-IR spectra showed that graphene did not contain oxygen-containing functional groups, such as: carboxyl, hydroxyl, carbonyl, etc. In contrast to micromechanical exfoliation, electrolytic exfoliation can be scaled up for large-scale and continuous production of graphene. In addition, differential pulse voltammetry （DPV） was used in simultaneous detection of dopamine （DA）, ascorbic acid （AA） and urine acid （UA）. DPV data indicated the superiorly electrocatalytic ability of the graphene. A novel graphene-based pH sensor was successfully fabricated by using graphene film. The open-circuit potential of graphene/AuE in different pH B-R buffer solution showed that the graphene/AuE can be used as a pH sensor with a linear range of pH 3.0¹1.0 and a sensitivity of 53.88 mV/pH.3) Fast and facile preparation of blue-green fluorescent carbon nanoparticles through electrochemical oxidation of graphite in ethanol was introduced The nanoparticles are characterized by Transmission electron microscopy （TEM）, FT-IR, Raman and other techniques. Surface energy traps were created on the carbon nanoparticles and resulted in the visible light emission due to the quantum confinement effects. Fluorescent carbon nanoparticles take on great potential in the application in biology labelling and life science due to their many advantages such as low cytotoxicity, biocompatibility, and chemically inert.4) Graphene nanosheets modified glassy carbon electrode （GNs/GCE） was fabricated as voltammetric sensor for determining rutin with good sensitivity, selectivity and reproducibility. The sensor exhibits an adsorption-controlled, reversible two-proton and two electron transfer reaction for the oxidation of rutin with a peak-to-peak separation （?Ep） of 26 mV as revealed by cyclic voltammetry. Moreover, the redox peak current increased about 14 times than that of bare glassy carbon electrode （GCE）. The linear response of the sensor is from 1×10-7 to 1×10^-5 M with a detection limit of 2.1×10-8 M （S/N=3）. The method was successfully applied to determine rutin in tablets with satisfied recovery.5) A highly sensitive and selective voltammetric sensor for simultaneous determination of hydroquinone （HQ） and catechol （CC） was developed by modifying a glassy carbon electrode with graphene nanosheets （GNs/GCE）. Separation of the oxidation peak potentials for HQ and CC was about 112 mV in 0.10 M acetate buffer solution （pH 4.5）, and the anodic currents for the oxidation of both HQ and CC are greatly increased at GNs/GCE, which makes it suitable for simultaneous determination of these compounds. Under the optimized conditions, the anodic peak current of HQ is linear with the concentration of HQ from 1×10^-6 to 5×10^-5 M in the presence of 5×10^-5 M CC. A detection limit of 1.5×10-8 M （S/N=3） can be achieved. At the same time, the anodic current of CC is linear with the concentration of CC from 1×10^-6 to 5×10^-5 M with a detection limit of 1.0×10-8 M （S/N=3） in the presence of 5×10^-5 M HQ. The proposed sensor was successfully applied to the simultaneous determination of HQ and CC in tap water, and the results are satisfactory.更多还原