N-掺杂—维多孔碳自组装及电催化氧还原反应

发布时间：2018-04-09 14:35

本文选题：碳化　切入点：量子点　出处：《大连理工大学》2016年硕士论文

【摘要】：氧还原反应(ORR)是大多数燃料电池及金属-空气电池的阴极反应,也是许多金属在腐蚀过程中的共轭反应。目前该反应催化性能最好的是铂基催化剂,但是由于其资源短缺和耐持久性差等缺陷严重制约其应用。因此,开发非金属类催化剂就显得尤为重要,掺杂型碳催化剂由于其独特的电子特性、多孔结构、丰富的碳源(如：有机化合物、金属有机框架(MOFs)材料、共价有机材料(COM))等特点而成为人们研究的热点。本课题利用模板法,设计并合成纳米纤维结构,并以此作为非金属催化剂的来源研究其在电催化氧还原反应中的应用。首先,以自组装的CdTe纳米线为牺牲模板,利用聚乙烯毗咯烷酮(PVP)与MOFs材料的相互作用诱导沸石咪唑类骨架结构ZIF-8(二价锌离子为配位中心,2-甲基咪唑为配体形成的六元环状结构)前驱物在其表面成核及生成从而形成CdTe@ZIF-8纳米纤维结构。其次,通过高温碳化CdTe@ZIF-8来制备氮(N)掺杂的一维中空/多孔碳结构。通过在0.1 M KOH电解液中对比直接从ZIF-8晶体中制备的N掺杂多孔碳与上述制备的一维中空/多孔碳结构的催化活性时,N掺杂的一维中空/多孔碳结构表现出更好的电催化活性,更高扩散极限电流密度和更正的半波电位。而导致其性能优越的原因是以CdTe@ZIF-8作为碳源时,由于其独特的电子结构使其在碳化过程中石墨化程度提高,并且在碳化过程中CdTe纳米线的挥发而留下的中空和多级多孔结构有利于其物质的传输。
[Abstract]:Oxygen reduction reaction (ORR) is the cathodic reaction of most fuel cells and metal-air cells, and is also the conjugation reaction of many metals in the process of corrosion.At present, the best catalyst is platinum-based catalyst, but its application is restricted seriously due to its shortage of resources and poor durability.Therefore, the development of non-metallic catalysts is particularly important. Due to their unique electronic properties, porous structure, rich carbon sources (such as organic compounds, organometallic frameworks and MOFss), doped carbon catalysts are very important.The characteristics of covalent organic materials have become the focus of research.In this paper, the structure of nanofibers was designed and synthesized by template method, and used as a non-metallic catalyst to study its application in electrocatalytic oxygen reduction reaction.First, using self-assembled CdTe nanowires as a sacrificial template,Nucleation and generation of zeolites imidazole framework structure ZIF-8 (hexagonal ring structure formed by divalent zinc ion as coordination center, 2-methylimidazole) on the surface of zeolite imidazole by the interaction of polyvinylpyrrolidone (PVP) with MOFs materialsThus, the structure of CdTe@ZIF-8 nanofibers was formed.Secondly, N-N doped one-dimensional hollow / porous carbon structure was prepared by carbonization of CdTe@ZIF-8 at high temperature.By comparing the catalytic activity of N-doped porous carbon prepared directly from ZIF-8 crystal with that of one-dimensional hollow / porous carbon structure prepared in 0.1m KOH electrolyte, the N-doped one-dimensional hollow / porous carbon structure showed better electrocatalytic activity.Higher diffusion limit current density and corrected half wave potential.The reason for its superior performance is that when CdTe@ZIF-8 is used as carbon source, the graphitization degree of CdTe@ZIF-8 is improved during carbonization because of its unique electronic structure.The hollow and multilevel porous structures left by the volatilization of CdTe nanowires during carbonization are beneficial to the transport of materials.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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