石墨烯基碳材料的制备与电容脱盐性能研究

发布时间：2018-02-01 05:43

本文关键词： 电容脱盐碳材料石墨烯复合材料　出处：《上海大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着人口的不断增长,环境污染的加剧,淡水资源已成为人类最大的威胁之一。海水及苦咸水脱盐淡化是解决水资源短缺的主要途径。电容脱盐是一种基于双电层电容原理的新技术,其具有成本低、能耗低、绿色无污染等特点。基于电容脱盐的原理,碳材料具有高比表面积、高导电性、稳定的物理及化学特性等是理想的电容脱盐电极材。本论文采用葡萄糖吹扫法合成制备了新型类石墨烯材料研究了其电容脱盐性能;为解决石墨烯易堆叠,将多孔碳引入石墨烯中制备了多孔碳/石墨烯复合材料,为了进一步提高复合材料的脱盐性能,制备了三维石墨烯/介孔碳球复合材料。考察了电极材料形貌结构与脱盐容量、脱盐效率和脱盐速率等的关系。主要内容如下:1)以葡萄糖为碳源,硝酸铁为石墨化催化剂,氯化铵为起泡剂,通过简单的“吹糖”工艺合成了高度石墨化的类石墨烯碳纳米片材料。它的片厚为2.4nm,约七个石墨层的厚度。作为对比,我们在相同实验条件下合成了只添加起泡剂而未添加硝酸铁催化剂的样品;以及直接煅烧葡萄糖得到的样品。研究了催化剂与起泡剂对样品电化学性能的影响。首先,通过研究电极在氯化钠溶液中的电吸附性能发现,相比于只添加起泡剂和什么都不添加的样品,类石墨烯纳米片的比电容最高。再次,通过充放电测试研究发现,相对于只添加起泡剂和什么都不添加的样品,类石墨烯纳米片的电极的循环稳定性和可逆性更加突出。类石墨烯纳米片这种良好的电化学性能主要源于材料具有较高的石墨化程度和较高的比表面积。最后,通过研究脱盐性能、动力学吸附参数、热力学吸附参数发现,类石墨烯纳米片电极不仅脱盐容量最大(38.62μmol/L)、吸附速率最快,而且其吸附以单层吸附为主。2)采用二氧化硅纳米粒子/氧化石墨复合材料为模板,通过简单的模板法合成了一种新型的氮掺杂的多孔炭/石墨烯基复合材料。氧化硅纳米粒子通过静电引力的作用吸附在石墨烯表面形成二氧化硅纳米粒子/氧化石墨复合材料,以此作为模版将掺杂氮元素的碳源包覆在模板外碳化,最后刻蚀掉氧化硅后形成了氮掺杂的多孔炭/石墨烯基复合材料。考察了复合材料中不同含氮多孔炭含量(31%、64%、72%、80%、90%)对电极电化学性能的影响。通过结构测试发现,复合材料中有均一介孔结构分布于层状的石墨烯上,并且材料的比表面积很高。通过循环伏安测试表明,当含氮多孔炭含量为72%时,复合材料的比电容最高,比单纯的石墨烯明显增大。通过充放电测试结果进一步发现,复合材料具有良好的循环稳定性和速率性能。此外,通过研究脱盐性能、动力学吸附参数、热力学吸附参数等也发现含氮多孔炭含量为72%的复合材料电极不仅脱盐容量比单纯石墨烯大、吸附速率比单纯石墨烯快,而且其吸附以单层吸附为主。3)采用硬模板法设计合成了一种三维石墨烯包覆的介孔碳球复合材料,以氧化硅包覆的介孔碳球作为硬模板,将氧化石墨通过静电引力吸附于模板表面形成三维结构,最后通过煅烧刻蚀形成复合材料。结构测试表明介孔碳球分散于三维石墨烯的空穴中,有效的防止了石墨烯片与片之间的团聚。电化学性能研究表明复合材料的比电容远大于单纯的三维石墨烯和介孔碳球。充放电结果进一步证明了复合材料的稳定性和可逆性也更加优良。另外,研究脱盐性能、动力学吸附参数、热力学吸附参数等也表明三维石墨烯包覆的介孔碳球复合材料电极不仅脱盐容量比单纯石墨烯和介孔碳球大、吸附速率也比单纯石墨烯和介孔碳球快,而且其吸附以单层吸附为主
[Abstract]:With the increase of population, the aggravation of environmental pollution, water resource has become one of the biggest threats to human beings. Seawater and brackish water desalination is the main way to solve the shortage of water resources. Desalination capacitor is a new technology based on the principle of electric double layer capacitor, which has the advantages of low cost, low energy consumption, pollution-free etc. based on the principle of capacitance. Desalination, carbon material with high surface area, high conductivity, stable physical and chemical characteristics of capacitor electrode material is ideal for desalination. This paper adopted glucose sweeping method to synthesize new type of graphene material on the capacitive desalination performance; in order to solve the problem of graphene is easy to stack the porous carbon into the graphene prepared porous carbon / graphene composite materials, in order to further improve the desalination performance of composite materials, three-dimensional graphene / mesoporous carbon spheres composite material was prepared. The influences of the shape of electrode materials The appearance and structure of desalination capacity, the relationship between the desalination efficiency and desalting rate. The main contents are as follows: 1) using glucose as carbon source, iron nitrate as graphitization catalyst, ammonium chloride as the foaming agent, through a simple "blown sugar" process highly graphitized synthesis of graphene like carbon nano materials. It film thickness is 2.4nm, about seven graphite layer thickness. As a comparison, we synthesized only add foaming agent without adding ferric nitrate catalyst samples under the same experimental conditions; and the samples obtained. Glucose direct calcination of catalyst and foaming agent effect on the electrochemical performance of the sample. Firstly, by electric adsorption performance of electrode in Sodium Chloride Solution found that compared to only add foaming agent and what are not added to the samples, the highest specific capacitance of graphene nanosheets. Thirdly, through the study of charge and discharge tests found that relative to only add up What do not add foaming agent and sample, cycle stability and reversibility of electrode type graphene nanosheets became more prominent. This kind of graphene nanosheets with good electrochemical performance is mainly due to the material with high graphitization degree and high surface area. Finally, through the research of the desalination performance, adsorption kinetics parameters found, thermodynamic adsorption parameters, type of graphene nanosheet electrode not only desalination capacity (38.62 mol/L), the adsorption rate is the fastest, and its adsorption to monolayer adsorption.2) using silica nanoparticles / graphene oxide composite material as a template, a new type of porous carbon / nitrogen doped graphene based composites were synthesized through the simple template method. Silica nanoparticles adsorbed by electrostatic interactions to form silica nanoparticles / graphene oxide composite material on the surface of graphene, as the template The nitrogen doped carbon coated carbide in the template, then etching the silicon oxide after the formation of the porous carbon / nitrogen doped graphene based composite materials. The effect of carbon content of porous composite materials with different nitrogen in (31%, 64%, 72%, 80%, 90%) effect on the electrochemical behavior of the electrode was found through. Structural testing, composite materials have the uniform mesoporous structure in layered graphene, and the surface area of the material is very high. The cyclic voltammetry tests show that when the nitrogen containing porous carbon content is 72%, the highest specific capacitance of the composite, than pure graphene significantly increased. Further found through the charge the discharge test results, composite material has good cycle stability and rate performance. In addition, through the study on desalination performance, adsorption kinetics parameters, thermodynamic parameters of adsorption were also found for nitrogen containing carbon content of porous composite electrode 72% not only desalination capacity Compared to the pure graphene, the adsorption rate than pure graphene, and its adsorption to monolayer adsorption.3) a mesoporous carbon composite three-dimensional ball coated with graphene was synthesized by the design method of die plate, coated with silicon oxide dielectric Kong Tanqiu as hard template, the oxidation of graphite by electrostatic adsorption form the three-dimensional structure on the surface of the template. Finally through calcination etching to form composite structure. Tests show that the mesoporous carbon spheres dispersed in three-dimensional graphene hole, effectively prevent between graphene sheet together. The electrochemical studies showed that specific capacitance of the composite is far greater than the simple three-dimensional graphene and mesoporous carbon spheres the charge and discharge. The results further demonstrate the stability and reversibility of the composites is more excellent. In addition, studies on desalination performance, adsorption kinetics parameters, thermodynamic parameters of adsorption also show three-dimensional graphene The coated mesoporous carbon sphere composite electrode not only has larger desalting capacity than pure graphene and mesoporous carbon spheres, but also has faster adsorption rate than pure graphene and mesoporous carbon spheres, and its adsorption is mainly monolayer adsorption.

【学位授予单位】：上海大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB33

【参考文献】