色氨酸功能化石墨烯的制备及其电化学传感器研究

发布时间：2018-04-04 21:04

  本文选题：石墨烯　切入点：色氨酸　出处：《西北师范大学》2015年硕士论文

【摘要】：石墨烯是碳原子以sp~2杂化形成的单层二维纳米材料。由于它具有高的导电性,大的比表面积,低廉的制备成本等使其成为一种理想的电化学材料。然而,石墨烯是疏水性的,在溶液中的分散性较差,而且石墨烯片层之间的范德华力和强烈的π-π堆叠作用使其趋于不可逆转的凝聚,甚至是重新堆叠为石墨,这些都限制了石墨烯的进一步应用。对石墨烯进行功能化,提高石墨烯在溶液中的分散性,是目前对于石墨烯材料应用的最主要的方法。本论文基于石墨烯的特性,利用色氨酸分子通过π-π作用功能化石墨烯,改善其分散性,提高电催化性能。将色氨酸功能化石墨烯修饰在电极表面,构建相应的传感器,用于抗坏血酸、多巴胺、尿酸的分别或同时检测,然后电沉积金纳米在色氨酸功能化石墨烯上,利用它们之间的协同作用,进一步提高电催化性能,用于多巴胺的检测。主要内容如下:1、基于色氨酸功能化的石墨烯用于检测抗坏血酸、多巴胺、尿酸基于色氨酸分子和石墨烯纳米片层之间的π-π共轭作用,通过简单超声的方法合成一种新型的色氨酸功能化的石墨烯纳米复合材料(Trp-GR)。这种材料与纯的石墨烯(GR)相比具有良好的水分散性和更高的导电性。扫描电子显微镜(SEM),透射电子显微镜(TEM)和拉曼光谱用来表征Trp-GR的表面形貌特征。抗坏血酸(AA)、多巴胺(DA)和尿酸(UA)在Trp-GR表面的电化学行为通过循环伏安法(CV)来表征。AA-DA、DA-UA和UA-AA之间的氧化峰电位分离分别约为182 mV、125 mV和307 mV,这使得AA、DA和UA可以同时测定。差示脉冲伏安法(DPV)被用于在AA、DA和UA的混合样品中检测AA、DA和UA。在最优化条件下,AA、DA和UA的检测线性范围分别为0.2~12.9 mM、0.5~110μM、10~1000μM,检出限分别为5.65μM、0.171μM和0.221μM。此外,该修饰电极被用于实际样品的检测。2、金纳米/色氨酸功能化的石墨烯用于灵敏检测多巴胺通过电化学沉积的方法将金纳米直接沉积在色氨酸功能化石墨烯上成功制备了一种简单且均一的金纳米/色氨酸功能化石墨烯(AuNPs/Trp-GR)纳米复合材料。AuNPs/Trp-GR的纳米结构通过扫描电子显微镜(SEM)和X射线能量分散能谱(EDS)进行了表征,证明金纳米均匀的分布在Trp-GR上,这可能是由于Trp-GR为金纳米的沉积提供了更多的结合位点。AuNPs/Trp-GR/GCE对多巴胺的电催化活性通过循环伏安法(CV)和差示脉冲伏安法(DPV)进行了系统的研究。在优化条件下,对于多巴胺的检测得到了一个较宽且有意义的线性范围(0.5~411μM)和一个较低的检测限(0.056μM),且具有良好的重复性和稳定性。此外,修饰电极还成功的用于对实际样品的分析。
[Abstract]:Graphene is a monolayer two-dimensional nanomaterials formed by sp~2 hybrid of carbon atoms.Because of its high conductivity, large specific surface area and low preparation cost, it is an ideal electrochemical material.However, graphene is hydrophobic and has poor dispersion in solution. Moreover, the van der Waals force and the strong 蟺-蟺 stacking between graphene layers lead to irreversible condensation and even restack to graphite.These all limit the further application of graphene.Functionalization of graphene to improve the dispersion of graphene in solution is the most important method for the application of graphene materials at present.In this paper, based on the properties of graphene, tryptophan molecules are used to functionalize graphene through 蟺-蟺 interaction to improve its dispersity and electrocatalytic performance.The tryptophan functionalized graphene was modified on the surface of the electrode, and a corresponding sensor was constructed to detect ascorbic acid, dopamine and uric acid separately or simultaneously, and then electrodeposited gold nanoparticles on the tryptophan functionalized graphene.The synergism between them can further improve the electrocatalytic performance and be used for the detection of dopamine.The main contents are as follows: 1. Graphene based on tryptophan functionalization is used to detect ascorbic acid, dopamine, uric acid based on 蟺-蟺 conjugation between tryptophan molecules and graphene nanoliths.A novel tryptophan functionalized graphene nanocomposite was synthesized by simple ultrasonic method.This kind of material has better water dispersibility and higher conductivity than pure graphene grass.Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy were used to characterize the surface morphology of Trp-GR.鎶楀潖琛，

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