多维掺杂碳材料的可控组装及其氧还原性能的研究
发布时间：2018-11-18 13:24
【摘要】：电催化氧还原反应是燃料电池阴极的一个重要的反应,由于其迟滞的动力学过程,成为限制燃料电池性能提升的关键步骤。因而,开发高效氧还原催化剂具有重大意义。对于氧还原反应来说,可以主要分为高效难发生的一步四电子反应及低效易发生第一步反应的两步两电子反应。由于两电子过程的第二步反应更难发生,且中间产物H_2O_2具有极强的催化剂毒性,因而制备具有四电子反应选择性,高效、高稳定性及低成本的氧还原催化剂是关键。本文致力开发具有优异电催化氧还原性能的碳基催化材料,通过掺杂引入催化活性位点进而控制四电子反应过程;构筑多维立体结构提高电解液的传输及电流的体相导电性;通过催化剂表面造孔及形成褶皱等方式降低碳材料的表面能,增强对氧气的吸附能力,同时增大了材料的比表面积。以呈不同电性的聚合物通过静电作用可控的构筑了一系列具有多维立体结构的高效碳基氧还原催化剂,实现了高效的四电子氧还原进程。在论文第一部分,我们通过使用聚对苯撑乙烯(PPV-precursor)作为前驱物,利用其水溶性及正电性通过插层修饰,水热自组装在石墨烯表面形成了聚合物球,最后经氨气气氛下高温焙烧,形成了薄层多褶皱的氮掺杂多孔石墨烯。研究发现,该电极材料较高的氧还原催化活性及循环稳定性。三维结构碳纳米催化剂由于结构上的优势(更大的比表面积,更稳定的催化剂材料结构)可以表现出比二维结构催化剂更优异的催化活性。在论文第二部分,我们研究了通过PPV-precursor的粘接作用,实现了三维N-RGO-PPV(c)-CNTs材料的构筑,并得到了更为稳固结构和更大的比表面积,得到了具有更多反应活性位点的氧还原催化剂。作为无铂非金属氧还原催化剂,N-RGO-PPV(c)-CNTs具有接近商业铂碳的起始电位(0.92V)及高于商业铂碳的极限电流密度(5.7m A*cm-2);此外,催化剂还具有优良的抗甲醇能力及循环稳定性,可以看出其具有大规模应用的前景。在论文第三部分,我们用聚乙酰亚胺(PEI)修饰氧化石墨使其表面带正电,通过静电作用可以使石墨烯量子点(GQDs)与氧化石墨烯进行有效的复合,进而形成具有二维立体结构的氧还原催化剂;GQDs的引入有效的阻止了石墨烯片层的聚集,提高了催化剂的比表面积;而小尺寸GQDs为催化剂提供了更多的活性位,进而提高了催化剂表面对氧气分子的吸附能。随后,我们通过一步水热法实现了硼氮杂原子的掺杂及氧化石墨的还原,制备了新型的具有氧还原催化潜质的硼氮共掺杂GQDs/石墨烯二维碳材料。
[Abstract]:Electrocatalytic oxygen reduction is an important reaction of fuel cell cathode. Because of its hysteresis kinetic process, it becomes a key step to limit the performance of fuel cell. Therefore, it is of great significance to develop high-efficiency oxygen reduction catalyst. For the oxygen reduction reaction, it can be divided into one step and four electron reaction which is highly efficient and difficult to occur, and two step two electron reaction which is easy to take place in the first step reaction with low efficiency. Because the second step of the two-electron process is more difficult to take place and the intermediate product H_2O_2 is highly toxic to the catalyst, the preparation of oxygen reduction catalyst with four-electron reaction selectivity, high efficiency, high stability and low cost is the key. This paper is devoted to the development of carbon-based catalytic materials with excellent electrocatalytic oxygen reduction performance, which can control the four-electron reaction process by introducing catalytic active sites into the catalyst, and construct multi-dimensional structures to improve the transport of electrolyte and the bulk conductivity of the current. The surface energy of carbon materials was reduced by making pores and forming folds on the surface of catalysts, and the adsorption ability of oxygen was enhanced, and the specific surface area of the materials was increased. A series of highly efficient carbon-based oxygen reduction catalysts with multi-dimensional structure were constructed by electrostatics with different electrical properties, and the process of four-electron oxygen reduction was realized. In the first part of the thesis, polymer spheres were formed by hydrothermal self-assembly on the surface of graphene by using poly (p-phenylene) (PPV-precursor) as precursor and by using its water-solubility and positive electrical properties through intercalation modification. Finally, nitrogen doped porous graphene was formed by calcination in ammonia atmosphere at high temperature. It is found that the electrode material has high catalytic activity and cycle stability for oxygen reduction. Three-dimensional carbon nanocatalysts exhibit better catalytic activity than two-dimensional catalysts due to their structural advantages (larger specific surface area and more stable structure of catalyst materials). In the second part of the thesis, we study the construction of 3D N-RGO-PPV (c)-CNTs materials by bonding of PPV-precursor, and obtain more stable structure and larger specific surface area. Oxygen reduction catalysts with more reactive sites were obtained. As a non-platinum non-metallic oxygen reduction catalyst, N-RGO-PPV (c)-CNTs has the initial potential of commercial platinum carbon (0.92V) and the limit current density of commercial platinum carbon (5.7m A*cm-2). In addition, the catalyst also has excellent methanol resistance and cycle stability, it can be seen that it has the prospect of large-scale application. In the third part of the thesis, we modify graphite oxide with polyimide (PEI) to make it have positive charge on its surface. By electrostatic action, we can effectively compound graphene quantum dot (GQDs) with graphene oxide. Then the oxygen reduction catalyst with two-dimensional stereoscopic structure was formed. The introduction of GQDs can effectively prevent the agglomeration of graphene layers and increase the specific surface area of the catalyst, while the small size GQDs provides more active sites for the catalyst, and thus increases the adsorption energy of oxygen molecules on the surface of the catalyst. Subsequently, the boron nitrogen hetero-atom doping and graphite oxide reduction were realized by one-step hydrothermal method. A novel boron-nitrogen co-doped GQDs/ graphene two-dimensional carbon material with oxygen reduction potential was prepared.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;O643.36
[Abstract]:Electrocatalytic oxygen reduction is an important reaction of fuel cell cathode. Because of its hysteresis kinetic process, it becomes a key step to limit the performance of fuel cell. Therefore, it is of great significance to develop high-efficiency oxygen reduction catalyst. For the oxygen reduction reaction, it can be divided into one step and four electron reaction which is highly efficient and difficult to occur, and two step two electron reaction which is easy to take place in the first step reaction with low efficiency. Because the second step of the two-electron process is more difficult to take place and the intermediate product H_2O_2 is highly toxic to the catalyst, the preparation of oxygen reduction catalyst with four-electron reaction selectivity, high efficiency, high stability and low cost is the key. This paper is devoted to the development of carbon-based catalytic materials with excellent electrocatalytic oxygen reduction performance, which can control the four-electron reaction process by introducing catalytic active sites into the catalyst, and construct multi-dimensional structures to improve the transport of electrolyte and the bulk conductivity of the current. The surface energy of carbon materials was reduced by making pores and forming folds on the surface of catalysts, and the adsorption ability of oxygen was enhanced, and the specific surface area of the materials was increased. A series of highly efficient carbon-based oxygen reduction catalysts with multi-dimensional structure were constructed by electrostatics with different electrical properties, and the process of four-electron oxygen reduction was realized. In the first part of the thesis, polymer spheres were formed by hydrothermal self-assembly on the surface of graphene by using poly (p-phenylene) (PPV-precursor) as precursor and by using its water-solubility and positive electrical properties through intercalation modification. Finally, nitrogen doped porous graphene was formed by calcination in ammonia atmosphere at high temperature. It is found that the electrode material has high catalytic activity and cycle stability for oxygen reduction. Three-dimensional carbon nanocatalysts exhibit better catalytic activity than two-dimensional catalysts due to their structural advantages (larger specific surface area and more stable structure of catalyst materials). In the second part of the thesis, we study the construction of 3D N-RGO-PPV (c)-CNTs materials by bonding of PPV-precursor, and obtain more stable structure and larger specific surface area. Oxygen reduction catalysts with more reactive sites were obtained. As a non-platinum non-metallic oxygen reduction catalyst, N-RGO-PPV (c)-CNTs has the initial potential of commercial platinum carbon (0.92V) and the limit current density of commercial platinum carbon (5.7m A*cm-2). In addition, the catalyst also has excellent methanol resistance and cycle stability, it can be seen that it has the prospect of large-scale application. In the third part of the thesis, we modify graphite oxide with polyimide (PEI) to make it have positive charge on its surface. By electrostatic action, we can effectively compound graphene quantum dot (GQDs) with graphene oxide. Then the oxygen reduction catalyst with two-dimensional stereoscopic structure was formed. The introduction of GQDs can effectively prevent the agglomeration of graphene layers and increase the specific surface area of the catalyst, while the small size GQDs provides more active sites for the catalyst, and thus increases the adsorption energy of oxygen molecules on the surface of the catalyst. Subsequently, the boron nitrogen hetero-atom doping and graphite oxide reduction were realized by one-step hydrothermal method. A novel boron-nitrogen co-doped GQDs/ graphene two-dimensional carbon material with oxygen reduction potential was prepared.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11;O643.36
【相似文献】
相关期刊论文 前10条
1 杨伟;陈胜洲;邹汉波;林维明;;氮掺杂非贵金属氧还原催化剂研究进展[J];化工进展;2010年11期
2 王丽娟;在石墨及聚酞菁化合物电极上氧还原的电催化[J];催化学报;1988年01期
3 黄幼菊;李伟善;黄青丹;李伟;张庆龙;蒋腊生;;氢钼青铜对铂催化氧还原反应的促进作用[J];高等学校化学学报;2007年05期
4 李之乐;曾为民;马玉录;;聚苯胺载铂钯电极的制备及氧还原催化性能研究[J];华东理工大学学报(自然科学版);2013年04期
5 李萍;李升宪;胡晓宏;王会勤;;球磨方法对氧还原催化剂性能的影响[J];电池;2006年03期
6 位辰先,田建华,梁宝臣,刘邦卫;制备条件对卟啉钴氧还原催化性能的影响[J];天津理工学院学报;2004年03期
7 孙晓然;李光跃;夏定国;张立美;李钒;;均苯四甲酰亚胺桥联的聚酞菁亚铁的氧还原反应(英文)[J];物理化学学报;2013年07期
8 左小刚;;硫酸盐还原菌对阴极氧还原反应的影响[J];新疆有色金属;2013年05期
9 张丽娟,夏定国,王振尧,袁嵘,吴自玉;铂铋金属间化合物催化剂的氧还原与抗甲醇氧化性能[J];物理化学学报;2005年03期
10 李英霞;陈章霖;罗瑞贤;陈霭t，
本文编号：2340141
本文链接：https://www.wllwen.com/kejilunwen/huagong/2340141.html
