铁钴氧化物纳米复合材料的制备及其电化学性能研究

发布时间：2019-01-24 14:30

【摘要】：纳米材料由于拥有纳米量级的尺寸优势,致使其在光热电力及磁学等方面都呈现出崭新的特性。纳米材料的诸多优点也致使由微观纳米粒子构成的体系中呈现出许多与宏观材料体系所属性质不同的新特性,这就使得人们对于自然科学系统的全面认识又步入了一个新的层次。随着新型纳米材料的研究过程的不断发展,过渡金属氧化物及其复合材料受到人们的密切关注。由于性能卓越,过渡金属氧化物所具有的潜在需求及其广阔的发展空间使其在电化学催化和生物传感等诸多领域具有毋庸置疑的重要性。此外,石墨烯由于具有非同寻常的优良性能,已经在纳米科学领域做出了卓越的贡献。纳米金属氧化物与石墨烯的复合在弥补了二者不足的同时彰显了材料各自的特性,不仅拓展了过渡金属纳米复合材料的研究,也开辟了新型材料更有价值的应用前景。基于以上论述,本论文主要开展了如下三部分工作:1.采用电化学沉积法在FTO导电玻璃基底上首次制备了具有一定厚度且形貌可控的铁掺杂的四氧化三钴薄膜。通过多种表征方法如SEM、TEM、XRD、XPS等对该材料的形貌、成分、晶型、价态等方面进行了系统的表征。探讨了不同沉积条件及退火温度对薄膜结构与性能的影响。所得的铁掺杂的四氧化三钴纳米薄膜表现出良好的氧还原催化活性。研究表明,铁的掺杂增加了材料中氧还原催化活性中心并且改善了薄膜对氧气的吸附性能。2.采用改进的Hummers法制备得到氧化石墨烯,进而通过化学一步还原法最终制得石墨烯/铁钴纳米复合材料,并对其进行物理表征和电化学测试。将该纳米复合材料用于构建H2O2无酶电化学传感器。实验结果表明,用石墨烯/铁钴纳米复合材料制备所得的该传感器具有响应速度快、灵敏度高、线性范围宽、检出限低等特点。对H2O2响应的浓度线性范围为2.0μM~3.2m M,检测限是1.0×10-7 M(S/N=3)。3.借助简单易操作的化学还原法,制备得到石墨烯/铁钴纳米复合材料修饰电极,采用阳极溶出伏安法对环境水样中的Cd~(2+)进行测定。同时考察了不同缓冲溶液、p H值、富集电位、富集时间、振幅和频率等条件对Cd~(2+)测定的影响。实验结果表明,在最优条件下,Cd~(2+)的响应电流与其浓度在1.8×10-8~1.20×10-6M以及1.2×10-6~2.0×10-5 M范围内呈良好线性,检出限为5.4×10-9 M(S/N=3)。所制备的r GO/Co3O4-Fe3O4纳米复合材料修饰电极重现性好,可用于Cd~(2+)的重复测定,同时为重金属离子的检测提供了一种新方法。
[Abstract]:Nanomaterials are in light due to their size advantages in nanometers. Hot Electricity? The force and magnetism all present the brand-new characteristic. The advantages of nanomaterials have also led to the emergence of many new properties that are different from those of macroscopical materials in the system composed of microcosmic nanoparticles. This makes people's comprehensive understanding of the natural science system into a new level. With the development of new nano materials, transition metal oxides and their composites have attracted close attention. Because of its excellent performance, the potential demand of transition metal oxide and its wide development space, it is undoubtedly important in many fields such as electrochemical catalysis and biosensor. In addition, graphene has made outstanding contributions in nanoscience due to its excellent properties. The composite of nano-metal oxide and graphene not only makes up for the shortcomings of the two materials, but also highlights the characteristics of the materials. It not only expands the research of transition metal nanocomposites, but also opens up a more valuable application prospect of new materials. Based on the above discussion, this paper mainly carried out the following three parts of work: 1. Fe doped Co _ 2O _ 4 thin films with a certain thickness and controllable morphology were prepared on FTO conductive glass substrate by electrochemical deposition for the first time. The morphology, composition, crystal form and valence state of the material were systematically characterized by various characterization methods such as SEM,TEM,XRD,XPS. The effects of deposition conditions and annealing temperature on the structure and properties of the films were discussed. The Fe doped cobalt trioxide nanocrystalline films exhibit good catalytic activity for oxygen reduction. The results show that the doping of iron increases the catalytic activity center of oxygen reduction and improves the oxygen adsorption performance of the film. 2. Graphene oxide was prepared by modified Hummers method, and then the graphene / Fe-Co nanocomposites were prepared by chemical one-step reduction method, and their physical characterization and electrochemical test were carried out. The nanocomposite was used to construct H2O2 enzymatic electrochemical sensor. The experimental results show that the sensor prepared by graphene / Fe-Co nanocomposites has the advantages of fast response, high sensitivity, wide linear range and low detection limit. The linear range for H2O2 response is 2.0 渭 m ~ 3.2m M and the detection limit is 1.0 脳 10 ~ (-7) M (S/N=3) 路3 ~ (-1). Cd~ (2) in environmental water samples was determined by anodic stripping voltammetry with graphene / Fe-Co nanocomposite modified electrode prepared by simple and easy to operate chemical reduction method. At the same time, the effects of, p H value, enrichment potential, enrichment time, amplitude and frequency of different buffer solutions on the determination of Cd~ (2) were investigated. The experimental results show that under the optimal conditions, the response current of Cd~ (2) is linear with its concentration in the range of 1.20 脳 10-6 M and 1.2 脳 10-6 M, and the detection limit is 5.4 脳 10-9 M (S/N=3). The prepared r GO/Co3O4-Fe3O4 nanocomposite modified electrode has good reproducibility and can be used for the repeated determination of Cd~ (2). It also provides a new method for the determination of heavy metal ions.
【学位授予单位】：西北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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