铁基复合纳米材料的制备及其电化学性能研究

发布时间：2018-06-22 10:23

本文选题：纳米复合材料 + 过渡金属氧族化合物　；参考：《江苏大学》2017年硕士论文

【摘要】：近年来,随着环境的污染和化石燃料的枯竭,为了减少对化石能源的依赖和提高能源的利用率,急切需要寻求清洁的能源供给和高效的能源转化。因而,提高超级电容器的电荷储存性能和电解水工业的催化剂活性已成为人们研究热点。过渡系金属氧化物和硫化物因其地球储量丰富,价格低廉,在催化/储能等领域的广泛应用前景而受到研究者的广泛关注。特别是,在含有多种金属组分的过渡金属基复合化合物中,金属组分间常常存在强的协同效应,这使得复合化合物具有增强的催化/传感/储能特性。利用过渡金属基复合化合物中的组分间协同作用,发展高效的电催化及电化学储能材料是当前的研究热点。本论文研究以铁基过渡金属基硫氧化物纳米复合材料作为研究对象,成功制备了Fe_3O_4@Co_9S_8/还原氧化石墨烯复合电催化剂及多孔Fe-Mn-O纳米复合材料。利用XRD,SEM,TEM,XPS等技术对其进行了系统表征。深入考察了Fe_3O_4@Co_9S_8/还原氧化石墨烯复合电催化剂的电催化水氧化析氧性能,多孔Fe-Mn-O纳米复合材料作为超级电容器电极的储能特性。具体如下:1.发展溶剂热方法合成了Fe_3O_4修饰的Co_9S_8纳米粒子/还原氧化石墨烯复合物(Fe_3O_4@Co_9S_8/rGO)。研究发现复合材料中铁组分的引入能影响硫化钴的物相。该复合材料表现出组分间协同作用增强的电催化水氧化析氧性能,在0.1 M KOH溶液中,电流密度为10 mA cm-2时复合材料的过电势仅为0.34 V,其塔菲尔斜率为54.5 mV decade-1,这远优于其他硫化钴材料。Fe_3O_4@Co_9S_8/rGO还具有较好的OER稳定性。基于XPS结果的分析表明,在Fe_3O_4@Co_9S_8/rGO催化剂中,电荷从Fe位点转移向Co位点,促使Co位点上最稳定的中间物Co-O-O易于脱附而促进催化性能的提高。2.通过聚合物前驱体途径借助煅烧处理成功制备了Fe-Mn-O复合材料。该复合物中,Fe和Mn组分均匀分布,复合物呈现多孔结构特征,其BET表面积高达72.7 m2 g-1。我们考察了Fe-Mn-O复合材料作为超级电容器电极的性能,在中性水溶液中,Fe-Mn-O复合材料电极具有较宽的工作电压窗口(-0.2到1.0 V),在电流密度为1 A g-1的条件下,其电容量可达86.7 F g-1或0.4 F cm-2,并有着好的稳定性。
[Abstract]:In recent years, with the pollution of the environment and the depletion of fossil fuels, in order to reduce the dependence on fossil energy and improve the utilization of energy, it is urgent to seek clean energy supply and efficient energy conversion. Therefore, it has become a hot research topic to improve the charge storage performance of supercapacitors and the activity of the catalyst in the electrolysis water industry. Transition metal oxides and sulfides are widely concerned by the researchers because of their abundant reserves and low prices, and widely used in the fields of catalysis and energy storage. Especially, in the transition metal matrix compound containing a variety of metal components, there are often strong synergistic effects between the metal components, which makes the compound compound It has enhanced catalytic / sensing / energy storage properties. The development of high efficient electrocatalytic and electrochemical energy storage materials using the synergistic effect of the transition metal matrix composite compounds is the current research focus. In this paper, the iron based transition metal based sulfur oxide nanocomposites have been used as the research object, and Fe_3O_4@Co_9S_8/ has been successfully prepared. The reduced graphene oxide composite electrocatalyst and porous Fe-Mn-O nanocomposites were characterized by XRD, SEM, TEM, XPS and so on. The performance of the electrocatalytic oxidation and oxygen evolution of the Fe_3O_4@Co_9S_8/ reduced graphite oxide composite electrocatalyst was investigated. The porous Fe-Mn-O nanocomposite was used as the electrode of the supercapacitor. The characteristics of energy storage are as follows: 1. the Fe_3O_4 modified Co_9S_8 nanoparticles / reduced graphene oxide complex (Fe_3O_4@Co_9S_8/rGO) has been synthesized by the development of solvothermal method. It is found that the introduction of iron component in the composite can affect the phase of cobalt sulfide. Performance, in 0.1 M KOH solution, the overpotential of the composite is only 0.34 V when the current density is 10 mA cm-2, and its Tafel slope is 54.5 mV decade-1, which is far superior to other cobalt sulfide materials.Fe_3O_4@Co_9S_8/rGO also has a good OER stability. Based on the analysis of XPS results, the charge is from the Fe site in the Fe_3O_4@Co_9S_8/rGO catalyst. Transfer to the Co site, prompting the most stable intermediate Co-O-O on the Co site to be easy to degenerate and promote catalytic performance,.2. has been successfully prepared through the calcining process by the polymer precursor pathway. In this complex, the Fe and Mn components are evenly distributed, the complex exhibits a porous structure, and its BET surface area is up to 72.7 M2 g-1.. We investigated the performance of Fe-Mn-O composite as a supercapacitor electrode. In neutral aqueous solution, the Fe-Mn-O composite electrode has a wide working voltage window (-0.2 to 1 V). Under the condition of the current density of 1 A g-1, the capacitance can reach 86.7 F g-1 or 0.4 F cm-2, and has good stability.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;TM53

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