基于层状氢氧化物构筑多功能碳纳米复合材料及其应用研究

发布时间：2018-04-03 15:43

  本文选题：碳纳米复合材料　切入点：层状氢氧化物　出处：《北京化工大学》2015年硕士论文

【摘要】：碳纳米复合材料有机结合了碳和纳米微粒两者优异的性能,因此在能量存储与转换、药物运载、环境、催化等领域有广泛的应用。目前碳纳米复合材料通常基于己制备的纳米碳材料(如石墨烯、碳纳米管)液相合成,存在制备工艺复杂、成本高、均匀性差、纳米微粒易团聚等缺点,因此,寻求一种简单高效的方法制备尺寸均匀、分散性高的碳纳米复合材料是亟需解决的重要课题。本论文以有机阴离子插层层状氢氧化物为单一前驱体,经一步固态热解可控合成及组装得到一种新型高质量、多功能的六方片状碳/金属/金属氧化物纳米复合材料,并将其应用于污染物去除和催化剂载体领域。主要研究内容如下：1.以水杨酸根(sal)插层的层状氢氧化物Co(Mg)Al-sal LDH为前驱体,无需还原剂和额外碳源一步固态热解得到六方片状C/Co/Mg(Al)O及C/Co/Al2O3纳米复合材料,研究金属元素比例、热解温度对复合材料组成和结构的影响。利用XRD、SEM、TEM、FT-IR、Raman、XPS、BET及VSM等表征手段对前驱体和碳纳米复合材料进行了详细表征。结果表明,得到的C/Co/Mg(Al)O纳米复合材料保持前驱体的六方片状结构,Co (8nm)和Mg(Al)O (3-5nm)纳米粒子均匀分散在石墨化的碳基底中；碳表面存在大量的-OH和-COOM,证明碳纳米复合材料表面功能化；具有较大的比表面积(600℃,207 m2/g)和丰富的孔结构；该碳纳米复合材料具有较高的饱和磁化强度,表现出优异的磁学性能。2.将C/Co/Mg(Al)O及C/CO/Al2O3内米复合材料应用于有机染料的去除,详细研究了焙烧温度、金属元素比例、溶液pH值和温度对吸附剂吸附效果的影响,并对其吸附机理进行探究。研究发现,该复合材料对阴离子染料刚果红、橙黄Ⅱ、甲基橙、伊文思蓝均表现出优异的吸附性能,如对染料刚果红,最大吸附量为2787mg/g,优于文献中报道的吸附材料；该纳米复合材料能够磁性回收并可多次重复利用。机理研究表明,该纳米复合材料中的Mg(A1)O表现出较高的活性,在水溶液中发生LDHs结构复原,大大提高其与染料的吸附位点,而且该材料表面存在大量的功能基团和丰富的孔结构使得C/Co/Mg(Al)O纳米复合材料对染料显示出优异的吸附性能。3.利用LDHs前驱体法一步固态热解得到六方片状C/Mg(Al)O纳米复合材料,经酸溶蚀,无需模板及催化剂的条件下得到新型六方片状石墨化多孔碳。对该碳材料进行一系列详细表征,结果表明,得到的碳材料具有较大的比表面积(658 m2/g)、丰富的孔结构、高石墨化程度且表面含有大量的功能基团-OH不-coo-,是一类理想的催化剂载体材料。在其表面负载Ag,无需还原剂即可原位得到六方片状C/Ag纳米复合催化剂,其中,Ag纳米微粒(8nm)均匀分散在多孔碳载体上。该催化剂在对硝基苯酚催化加氢反应中表现出较高的催化活性和稳定性。
[Abstract]:Carbon nanocomposites have been widely used in energy storage and conversion, drug delivery, environment, catalysis and so on.At present, carbon nanocomposites are usually based on liquid phase synthesis of nano-carbon materials (such as graphene, carbon nanotubes), which have the disadvantages of complex preparation process, high cost, poor homogeneity and easy agglomeration of nanoparticles.It is an important task to find a simple and efficient method to prepare carbon nanocomposites with uniform size and high dispersion.In this paper, a new high quality, multifunctional hexagonal carbon / metal / metal oxide nanocomposite was synthesized and assembled by one-step solid pyrolysis with organic anion intercalated layered hydroxides as a single precursor.It is applied to the field of pollutant removal and catalyst support.The main research contents are as follows: 1.Using layered hydroxide Co(Mg)Al-sal LDH intercalated with salicylic acid as precursor, hexagonal C/Co/Mg(Al)O and C/Co/Al2O3 nanocomposites were prepared by one step solid pyrolysis without reducing agent and extra carbon source.Effect of pyrolysis temperature on composition and structure of composites.The precursor and carbon nanocomposites were characterized in detail by means of XRDD-SEMM-TEMT-IRT- Ramanhe XPS-BET and VSM.The results show that the prepared C/Co/Mg(Al)O nanocomposites keep the precursor hexagonal sheet structure (8nm) and Mg(Al)O (3-5nm) nanoparticles dispersed uniformly in graphitized carbon substrates, and there are a large number of -OH and -COOM on the carbon surface, which proves the functionalization of the carbon nanocomposites.It has a large specific surface area of 600 鈩，

本文编号：1705855