多孔石墨烯的制备及其电化学性能的研究

发布时间：2018-07-25 17:29

【摘要】：目前,随着太阳能、风能、热能等环境友好型可再生清洁能源的高速发展,研究和开发具有绿色环保、高能量密度和高功率密度特点的新型能量存储装置,已经成为新能源产业发展的关键环节。其中超级电容器和氢燃料电池具有传统储能器件不可比拟的优点,在近年来得到了广泛的研究。面内多孔石墨烯面内的孔结构在离子传输扩散方面有着传统石墨烯不可比拟的优势。本文探索了基于缺陷结构石墨相材料制备面内多孔石墨烯的化学合成方法,并对其作为超级电容器电极材料电化学储能特性进行了表征,同时研究了氮掺杂面内多孔石墨烯负载钴复合材料体系的电催化制氢特性,主要研究内容如下:1.以高缺陷的微晶石墨或碳纳米管作为前驱体,基于改进Hummers法制备了多孔石墨烯氧化物。利用石墨相材料内部丰富的sp3碳缺陷,通过少步氧化处理制备了具有面内孔结构的氧化石墨烯。面内孔结构缩短了离子扩散的路径,有利于电解质离子通过扩散进入到石墨烯的表面,有效地促进电荷的传输,提高了电极活性。结果表明,在0.1A/g和100 A/g的充放电电流下其电容分别高达375F/g(439F/cm3)和196 F/g(229F/cm3)。此外以碳纳米管为前驱体制备的多孔石墨烯可以实现对其面内孔尺寸的调控,从而为研究多孔结构对石墨烯电催化活性的影响提供了材料制备途径。2.以具有不同尺寸面内孔的多孔氧化石墨烯为前驱体,通过氮掺杂和钴复合,研究了不同石墨烯孔尺寸对调控氮掺杂的影响,并测试了其负载钴电催化制氢的性能。研究了此复合材料的制备方法,合成条件对元素掺杂、化学键合形式、石墨烯表面分布形态的影响。通过石墨烯面内结构调控和过渡金属复合以及氮掺杂石墨烯制备低金属含量、高性能电催化制氢催化剂。其在0.5M H2SO4酸性体系表现出优异的催化活性:Tafel斜率低至64mV dec-1,获得10mA cm-2的电流密度所需的过电位仅为-203mV。
[Abstract]:At present, with the rapid development of environment-friendly renewable clean energy such as solar, wind and heat, new energy storage devices with green, high energy density and high power density are researched and developed. It has become a key link in the development of new energy industry. Supercapacitors and hydrogen fuel cells have been widely studied in recent years because of their incomparable advantages over conventional energy storage devices. In-plane porous graphene has incomparable advantages over traditional graphene in ion transport and diffusion. In this paper, the chemical synthesis method of in-plane porous graphene based on defect structure graphite phase material was investigated, and its electrochemical energy storage characteristics as electrode material of supercapacitor were characterized. At the same time, the electrocatalytic hydrogen production characteristics of nitrogen-doped porous graphene supported cobalt composite system were studied. The main research contents are as follows: 1. Porous graphene oxide was prepared by modified Hummers method using highly defective microcrystalline graphite ink or carbon nanotubes as precursors. Graphene oxide with in-plane pore structure was prepared by using sp3 carbon defects in graphite phase. The in-plane pore structure shortens the path of ion diffusion, which is beneficial to the diffusion of electrolyte ions to the surface of graphene, which can effectively promote the charge transfer and improve the electrode activity. The results show that at the charge / discharge current of 0.1A/g and 100A / g, the capacitance is as high as 375F/g (439F/cm3) and 196F / g (229F/cm3), respectively. In addition, porous graphene prepared with carbon nanotubes as precursor can regulate the in-plane pore size of graphene, which provides a way to study the effect of porous structure on the electrocatalytic activity of graphene. 2. Using porous graphene oxide with different in-plane pores as precursor, the effect of different graphene pore sizes on nitrogen doping was studied by nitrogen doping and cobalt compounding, and the performance of supported cobalt electrocatalysis for hydrogen production was tested. The preparation method of the composites and the effects of the synthesis conditions on the doping of elements, the form of chemical bonding and the surface distribution of graphene were studied. Low metal content and high performance electrocatalytic catalysts for hydrogen production were prepared by in-plane structure control of graphene, transition metal composite and nitrogen-doped graphene. It shows excellent catalytic activity in 0.5m H2SO4 acid system. The slope of 64mV dec-l is lower than that of 64mV dec-1, and the overpotential required to obtain the current density of 10mA cm-2 is only -203 MV.
【学位授予单位】：中国地质大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11

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