一维新型电极材料的设计及其电化学性能研究

发布时间：2018-01-09 11:33

本文关键词：一维新型电极材料的设计及其电化学性能研究　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：随着化石燃料的不断消耗和环境污染的日益加重,开发清洁能源已经成为二十一世纪最重要的问题之一。发展廉价、环保、高效的能源存储与转换材料是解决这一问题的重要途径。纳米科技的迅速发展给能源领域带来了新的机遇与挑战,科学家们已经在新型纳米电极材料的制备和应用研究方面取得了重要进展。尽管如此,如何合理的设计电极材料,以及如何实现电极材料结构与性能的优化,仍是目前亟待解决的关键问题。一维纳米结构电极材料具有较高的比表面积、短的电子传输路径、易于形成三维网络等优势,在电化学能源存储与转换领域有着十分广泛的应用。本论文将着重探讨几种一维电极材料的设计、制备及其在电化学能源储存与转换领域中的应用。首先以本实验室发展的一种高度均匀的碳质纳米纤维作为前驱体,通过合理的杂原子掺杂制备出性能优异的超级电容器电极材料。而后利用化学刻蚀和退火处理等方法制备出一系列中空纳米管状能源存储电极材料。此外,以廉价的钼酸镍(NiMoO_4)纳米棒做为前驱体,结合碳包覆和三维基底原位生长技术,分别制备了多孔碳负载镍钼金属颗粒和镍钼氧化物纳米棒阵列两种催化剂。该电极材料作为双功能的电化学产氢和产氧催化剂,有望应用于电化学全水分解制氢反应。所取得的主要研究成果如下:1、通过合理的杂原子掺杂,制备出具有三维网络结构的硼氧共掺杂碳纳米纤维(BO-CNF)薄膜材料,实现了超级电容器性能的提升。在本实验室发展的碳纳米纤维基础上,我们利用简单的前驱体混合和高温碳化过程,成功制备出自支撑的BO-CNF薄膜。我们通过调节杂原子的掺杂含量和薄膜材料的振实密度,获得了具有高的质量比电容(192.8 Fg-1)和体积比电容(179.3 Fcm3)的电极材料,并详细阐述了材料微观结构与电化学性能之间的关系。该薄膜材料由于具有连续的电解质离子扩散通道以及良好的电导率,因而具有非常高的倍率容量。同时,这种薄膜材料可作为一种良好的载体平台来沉积比容量更高的聚苯胺纳米颗粒,实现性能的进一步提升。我们还展示了所用硼源掺杂剂的循环再利用过程,达到了降低生产成本的目的。2、发展了两种制备金属氧化物、氢氧化物空心微纳米管的方法。以碳纳米纤维为模板,通过原位包覆和低温化学刻蚀,我们成功制备出具有较高比表面积(221.8m2g-1)的氢氧化镍(Ni(OH)_2)空心纳米管结构,并详细讨论了刻蚀条件对材料结构的影响。该方法具有很好的普适性,可用于制备其它钴基和锰基金属氧化物空心纳米管;另外通过层层生长法,即在一种钼基金属-有机框架(MOF)纤维的表面原位生长另一种钴基MOF,构筑出包覆层厚度不同的MOF核壳结构。然后利用热处理和碱刻蚀过程,制备出具有多级结构的混合金属氧化物(CoMoO_4)亚微米管。利用上述几种过渡金属空心管材料高比表面积和大孔隙率的优势,探讨了其在超级电容器、锂离子电池电极材料上应用的可能性。3、成功制备出一维多孔碳负载过渡金属的全水分解催化剂材料。以廉价的NiMoO_4纳米棒作为前驱体,通过常温碳包覆并结合高温碳化处理,制备了一种多孔碳负载镍和碳化钼纳米颗粒(Ni/Mo_2C-PC)的复合催化剂。该复合材料作为一种双功能电催化剂,展现出良好的氢析出(HER)和氧析出(OER)催化活性。通过材料组分与性能关系的详细研究,我们发现该复合材料高的催化活性来源于Ni与Mo_2C之间的电子迁移。这种电子转移导致了更高价态的镍和更低价态的钼,从而形成更多的HER和OER的活性位点。全水分解产氢电解槽具有良好的活性和稳定性,有望应用于电解水制氢反应。4、发展了一维金属氧化物纳米棒阵列材料的尿素电解产氢性能。以生长在泡沫镍上的NiMoO_4纳米棒阵列为前驱体,通过在不同气氛下的退火处理,分别得到了用于尿素电解制氢反应的阳极和阴极催化剂。该阳极催化剂包含高价态的镍离子和钼离子,能够有效地催化尿素氧化反应(UOR),用于取代通常电解水中的阳极OER过程,可大大降低反应的电压值。其阴极催化剂由于具有镍钼复合价态的HER多重活性位点,表现出可与最好的铂碳催化剂相媲美的催化活性。因而组装成的尿素电解槽仅需极低的槽电压就能获得高的电流密度,实现了基于非贵金属催化剂材料电解槽的性能最优化。这些三维块材催化剂材料避免了粘结剂的加入和催化剂的涂覆,具有极高的活性和稳定性,展现出良好的应用前景。
[Abstract]:With the continuous consumption of fossil fuel and environmental pollution is increasing, the development of clean energy has become one of the most important problems. In twenty-first Century the development of low-cost, environmentally friendly, energy storage and conversion efficiency of the materials is an important way to solve this problem. The rapid development of nanotechnology has brought new opportunities and challenges to the field of energy, scientists important progress has been made in the new nano electrode materials preparation and application research. However, how to design the electrode material reasonably, and how to realize the optimization of material structure and properties of the electrode, is a key problem to be solved. One dimensional nanostructured electrode materials with high specific surface area, the electronic transmission path is short that is easy to form a three-dimensional network and other advantages, has been widely used in electrochemical energy storage and conversion field. This paper will focus on The design of several one dimensional electrode material, preparation and its application in electrochemical energy storage and conversion in the field. First developed by our laboratory and a highly uniform carbon nanofibers as the precursor, through reasonable heteroatom doping in preparing excellent electrode materials of supercapacitor. Then using chemical etching and annealing treatment the methods for the preparation of a series of hollow nano tubular energy storage materials. In addition, the inexpensive nickel molybdate (NiMoO_4) nanorods as precursor, carbon coating and substrate with three-dimensional in-situ growth technique, were prepared porous carbon supported nickel molybdenum metal particles and nickel molybdenum oxide nanorod arrays of two kinds of catalysts. The electrode materials as electrode hydrogen and oxygen producing double function catalyst, is expected to be applied to the electrochemical hydrogen reaction. The main results are as follows: 1, through the reasonable Heteroatom doping, preparation of boron oxygen with three dimensional network structure of Co doped carbon nanofibers (BO-CNF) thin film materials, realizes the super capacitor performance improvement. In the laboratory the development of carbon nanofibers on the basis, we use the mixed precursor and high temperature carbon process simple, prepared by BO-CNF the film we support. By adjusting the heteroatom doping concentration and film material tap density, obtained with high quality capacitance (192.8 Fg-1) and the volume ratio of the capacitor (179.3 Fcm3) of the electrode material, and expounds the relationship between the microstructure and the electrochemical properties of the material. The film material with electrolyte the continuous ion diffusion channels and good conductivity, so it has very high rate capacity. At the same time, the polystyrene film material can be used as a good platform to deposit higher than capacity Amine nanoparticles, to further enhance the system performance. We also show the source of boron dopant recycling process, to reduce the cost of production of.2, developed two kinds of preparation methods of metal oxide, hydroxide hollow nanotubes. Using nano carbon fiber as the template, through in situ coating and low temperature chemical the etching, we successfully prepared with high specific surface area (221.8m2g-1) of nickel hydroxide (Ni (OH) _2) hollow nanotubes, and the effects of etching conditions on the structure of the material is discussed. This method has good universality, can be used for the preparation of other cobalt and manganese based metal oxide hollow nanotubes in addition; layer by layer growth method, namely in a molybdenum based metal organic frameworks (MOF) another cobalt based MOF surface in situ fiber, construct MOF core-shell structure of the coating layer of different thickness. Then by means of heat treatment and alkali The etching process, preparation of mixed metal oxides with hierarchical structure (CoMoO_4) sub micron tube. By using the above several transition metal hollow tube material with high specific surface area and high porosity advantage, it discusses the super capacitor electrode material of lithium ion battery application can.3, successfully prepared porous carbon supported transition metal water decomposition catalyst materials. Using cheap NiMoO_4 nanorods as precursor, carbon coated with high temperature and normal temperature through carbonization, prepare a porous carbon supported nickel and molybdenum carbide nanoparticles (Ni/ Mo_2C-PC) of the composite catalyst. The composite material as a bifunctional electrocatalyst, show a good hydrogen evolution (HER) and oxygen precipitation (OER) catalytic activity. Through the detailed study of material composition and property, we found that the composites with high catalytic activity between Ni and Mo_2C from Electron transfer electron transfer. This leads to more and more high valence nickel low valence molybdenum, the active site to form more HER and OER. The hydrogen from electrolysis cell has good activity and stability, can be used in the water electrolysis reaction of.4, the development of the urea electrolytic hydrogen production properties of one-dimensional metal oxides nanorod array materials. Using NiMoO_4 nanorod arrays grown on nickel foam as precursor by annealing under different atmosphere, were obtained for the anode and cathode catalyst for hydrogen production. The urea electrolytic nickel ion and molybdenum ion of the anode catalyst contains high valence, can effectively catalyze the oxidation reaction of urea (UOR), anode for OER process instead of electrolytic water, can greatly reduce the reaction voltage. The cathode catalyst due to HER multiple active sites with nickel molybdenum composite valence, exhibit The catalytic activity can be comparable with the platinum carbon catalyst. The best electrolytic cell assembled and urea only very low cell voltage can obtain high current density, the performance optimization of non noble metal catalyst material in electrolytic bath. Based on these 3D bulk catalyst materials to avoid coating binder and adding catalyst, has high activity and stability, show a good application prospect.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O643.36;O646

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