铁族合金及其复合材料的制备及污水处理和超级电容性能研究

发布时间：2018-03-23 13:28

本文选题：吸附剂　切入点：催化剂　出处：《吉林大学》2017年博士论文

【摘要】：随着城市化和生活水平的不断提高,全球能源消耗和环境负担急剧增加。用可再生能源代替传统能源是解决能源和相应环境问题的一种重要方法,既能减少污染物的产生又能满足能源需求。含有有机染料污染物废水的数量已经远远超出了生态系统的自我修复能力。迄今为止,一些物理,化学和生物类的处理方法已经被广泛研究,其中涌现出了大量具有实际应用潜力的候选材料。然而实验研究与实际应用之间仍然存在极大的差距,例如,制备工艺昂贵和制备过程的复杂性,以及低的降解效率,同时也有可能引起二次污染。此外,随着对高能量和功率密度存储器件不断增长的需求,有必要在充电电池和超级电容器的科学技术上获得突破性进展,来满足未来低碳和可持续经济的发展目标。针对以上的挑战,本文制备了几种铁族合金和其复合物材料来缓解面临的环境问题和能源危机。本文系统的对材料的结构,形貌以及反应机理和性能等进行了研究。主要研究内容如下:(1)八面体结构的CoFe/CoFe_2O_4亚微米级复合物通过一种灵巧的一步水热法制备,作为催化过一硫酸盐(PMS)的异质催化剂,能将污水中含有的有机污染物降解。经过本实验的研究,在“CoFe/CoFe2O4+PMS”体系的氧化反应过程中硫酸根(SO4·-)和羟基自由基(·OH)同时参与降解有机污染物。无毒性的CoFe/CoFe2O4亚微米复合物能高效降解溶液中的橙黄II。并对CoFe/CoFe2O4作为PMS催化剂的催化机理进行了系统的分析。CoFe/CoFe2O4复合物出众的催化性能,优异的重复利用性和稳定性,更广泛的普遍适用性和磁回收性能使其成为环境矫正中的候选催化剂材料。(2)通过简单的室温硼氢化钠还原法制备了一系列室温稳定的Co_xNi_(1-x)(x=0,0.2,0.4,0.6,0.8 and 1)双金属合金纳米颗粒。通过调节制备的Co_xNi_(1-x)双金属纳米颗粒的化学组成,研究了样品对含有刚果红的污水的吸附能力。具有铁磁性能的Co_xNi_(1-x)合金纳米颗粒能够将溶液中的刚果红快速高效的移除,在吸附过程结束后,可以用磁体将吸附后的物质从水溶液中快速分离出来。化学组成为Co0.6Ni0.4的双金属合金纳米颗粒显示了最高的吸附效率。并且吸附过程中,化学吸附与静电吸附同时发生,其中化学吸附占主导地位。此外,应用密度泛函理论计算的辅助,对Co0.6Ni0.4双金属合金的优异吸附效率进行了深入研究。在计算中,建立了一系列的表面模型用以对比表面能、功函数、态密度和表面电子差分密度之间的差异。通过对表面电子结构的进一步研究,表明化学组成和表面缺陷对d带中心具有重要的影响,恰当的d带结构对吸附性能有直接的影响。结合实验和理论计算的结果进一步证明了Co0.6Ni0.4合金比单金属具有优秀吸附性能的原因,也表明Co0.6Ni0.4合金可以作为商业化大规模的磁性吸附剂使用。(3)本工作中,通过一种新奇的方法制备了一系列的钴镍双金属/钴-镍氧化物@碳(M/MO@C)结构的复合物。以吸附刚果红分子的CoNi纳米颗粒复合物作为前驱体,经高温氮气气氛下的煅烧制备了M/MO@C复合物。以制得的复合物作为超级电容器的电极材料,通过电化学性能测试,确定了具有最佳电化学性能的材料中Co_xNi_(1-x)合金的最佳化学组成是Co0.2Ni0.8,最佳煅烧温度为600oC。在最佳制备条件下获得的具有薄片状结构的M/MO@C-600复合物在1 A g~(-1)的电流密度下的比容量可达1134.9 F g~(-1),在10 A g~(-1)的电流密度下循环充放电2000圈后,其容量可保留初始容量的66%。此外,以M/MO@C-600复合物为正极,商用活性炭作为负极组装了非对称电容器。非对称电容器在0.5 A g~(-1)的电流密度下比容量可达111.2 F g~(-1),在功率密度为0.425 Kw kg~(-1)时其能量密度可达44.6 Wh kg~(-1)。在6 A g~(-1)的电流密度下循环充放电10000圈后非对称电容器的比容量可基本保持100%。本文提出的制备方法摒弃了传统方法中使用的碳源,以有机染料刚果红分子作为碳源成功制备出的M/MO@C-600复合物可用作超级电容器的电极材料,实现了污水处理产生的副产物作为绿色能源存储材料的二次利用,这种经济绿色环保的制备方法可同时缓解来自于环境和能源方面的压力。
[Abstract]:With the city and the continuous improvement of living standards, the global energy consumption and environmental burden increased dramatically. With the renewable energy to replace traditional energy is an important way to solve the energy and environmental problems, which can not only reduce the generation of pollutants and can meet the demand for energy. There are a number of wastewater containing organic dye pollutants has far exceeded the self repair the capacity of the ecological system. So far, some physical, chemical and biological treatment methods of the class has been extensively studied, including the emergence of a large number of candidate materials has application potential. However, experimental research of great gap still exists between the research and practical application for example, the complexity of preparation process of preparation process and expensive system, and low degradation efficiency, but also may cause two pollution. In addition, with the continuous growth of high energy and power density memory requirements, it is necessary to Breakthrough in battery and super capacitor in science and technology, to meet the objectives of the future development of low carbon and sustainable economy. In view of the above challenges, this paper prepared several iron group alloys and its composites to ease the energy crisis and environment problem. In this paper the structure of material. The morphology and the reaction mechanism and properties were studied. The main contents are as follows: (1) CoFe/CoFe_2O_4 sub micron composite eight surface structure by a one-step hydrothermal method to prepare as smart, a catalytic sulfate (PMS) heterogeneous catalyst can decompose organic pollutants in wastewater. After the experiment, in the oxidation process of CoFe/CoFe2O4+PMS system in sulfate (SO4 -) and hydroxyl radical (- OH) are also involved in the degradation of organic pollutants. The non-toxic CoFe/ CoFe2O4 submicron complex Compound capable of degrading solution of orange II. and CoFe/CoFe2O4 as the catalytic mechanism of PMS catalyst for the catalytic performance of complex.CoFe/CoFe2O4 system analysis outstanding, excellent reusability and stability, wide universality and magnetic recovery performance has been corrected in the environment (2) candidate catalyst material. A series of room temperature stable Co_xNi_ were prepared at room temperature by a simple reduction of sodium borohydride (1-x) (x=0,0.2,0.4,0.6,0.8 and 1) bimetallic alloy nanoparticles. By adjusting the preparation of Co_xNi_ (1-x) chemical composition of bimetallic nanoparticles, were studied with Congo red sewage adsorption capacity with iron. The magnetic properties of Co_xNi_ (1-x) alloy nanoparticles in solution can be fast and efficient removal of Congo red, in the adsorption process is finished, can be adsorbed from aqueous solution with magnet material Fast separation. The chemical composition of bimetallic alloy nanoparticles of Co0.6Ni0.4 showed the highest adsorption efficiency and adsorption process, chemical adsorption and electrostatic adsorption occurred at the same time, the chemical adsorption is dominant. In addition, the auxiliary calculation using density functional theory, excellent adsorption efficiency of Co0.6Ni0.4 bimetallic alloy are studied in the calculation, set up a series of surface model is used to compare the surface energy, work function, state density and surface electron density difference between. Through further research of surface electronic structure, chemical composition and surface defects that have important effect on the D center, d with the proper structure directly the influence on the adsorption performance. Combined with the experimental and theoretical results prove that Co0.6Ni0.4 alloy has excellent adsorption properties than the single metal, also shows that Co0.6Ni0 As a commercial magnetic adsorbent mass using.4 alloy. (3) this work, through a novel method to prepare a series of double metal cobalt and nickel / cobalt - nickel oxide @ carbon (M/MO@C) composite structure. The CoNi nano particle compound molecules for adsorption of Congo red the precursor and calcined at high temperature under nitrogen atmosphere to prepare M/MO@C composites. The composites prepared as electrode material for supercapacitor, by electrochemical performance test, to determine the Co_xNi_ has the best electrochemical performance of the materials (1-x) the best chemical composition of the alloy is Co0.2Ni0.8, the optimum calcination temperature for 600oC. in the best the preparation conditions for M/MO@C-600 composite materials with lamellar structure at 1 A g~ (-1) of the current density is lower than the capacity of up to 1134.9 F g~ (-1), A g~ (-1) 10 in the current density cycle after 2000 charge discharge cycles, the capacity retention In addition to the initial capacity of 66%., M/MO@C-600 composite cathode and commercial activated carbon as anode assembly of asymmetric capacitor. The asymmetric capacitor at 0.5 A g~ (-1) of the current density than the capacity of up to 111.2 F g~ (-1), the power density is 0.425 Kw kg~ (-1) when the energy the density of up to 44.6 Wh kg~ (-1). In 6 A g~ (-1) of the current density cycle after 10000 charge discharge cycles asymmetric capacitance can basically keep the preparation method of 100%. is proposed in this paper to abandon the use of traditional methods of organic carbon source, with Congo red dye molecules as the electrode materials of M/MO@C-600 composite material prepared can be used as a carbon source for the super capacitor, the by-product of wastewater treatment as the two use of green energy storage material and preparation method of the green economy can also relieve pressure on the environment and energy aspects.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TG139;TB33

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