燃料电池的非铂基催化剂制备及其电化学性能

发布时间：2018-03-29 00:27

本文选题：能源　切入点：燃料电池　出处：《吉林大学》2015年博士论文

【摘要】：能源是人类社会存在和发展必不可少的物质基础。随着社会的发展，能源在日渐减少，同时引发各种环境问题，这必将会阻碍人类社会经济的发展。因此，围绕着3E(Economy,Energy,Environment)寻找新的能源是非常有必要的。燃料电池有着能量密度高、低污染、方便充电、结构简单，在低温下也能快速启动，能量转换过程不需要经过卡诺循环，可以直接将化学能转换为电能的装置，这符合绿色能源的条件。目前，，Pt以及PtM/C催化剂广泛应用于燃料电池中的各种电催化反应：醇类燃料电池的阳极氧化；氢气燃料电池中正极以及制备氢气的析氢反应(HER)以及燃料电池的阴极氧还原(ORR)等等。但是，世界上Pt储量有限，价格昂贵，并且Pt催化剂在醇类燃料电池中对甲醇的氧化反应(MOR)中的中间产物CO容易中毒；在燃料电池的阴极中，阳极为甲醇时容易产生“跨界反应”，催化剂失活等特点，大规模地发展Pt型燃料电池非常困难。因此，探索制备新的非铂电催化剂至关重要。如何提高催化剂的催化活性，开发新的非贵金属催化剂已经成为燃料电池发展的长期研究课题之一。本文主要围绕燃料电池中的非铂基催化剂的制备进行了研究。首先，在无有机模板条件下使用四乙基氢氧化铵(TEAOH)合成的Beta分子筛(Beta-TEA)作为晶种来诱导制备富铝的Beta分子筛(Beta-SDS)，通过离子交换制备了Ni-Beta分子筛。通过研究表明Beta-SDS因为富铝，离子交换能力大，可以引入更多的镍离子(Ni2+)。通过循环伏安法和计时电流法，在碱性溶液中Ni-Beta-SDS电极对甲醇的氧化反应(MOR)的电催化活性明显高于用传统的Ni-Beta-TEA。其次，利用无模板水热法制备具有大表面积的多级孔的urchin-like状的钴酸镍(NiCo2O4)。通过循环伏安法和计时电流法，在碱性溶液中NiCo2O4对MOR的电催化活性明显高于单一的金属氧化物氧化镍(NiO)和四氧化三钴(Co3O4)。再次，通过添加氟化铵(NH4F)改变形貌制备了nanosheet状的二硫化钼(MoS2)。在硫酸溶液中进行了析氢反应(HER)的测试，研究结果表明nanosheet状的MoS2由于其薄片从而使暴露出更多的活性位，比没有添加NH4F制备的块状MoS2具有更好的电催化活性。最后，在高温退火氧化聚六亚基胍(PHMB)与氧化石墨烯(GO)的混合物，制备了氮掺杂的石墨烯(N-Graphene)，并在碱性溶液中对氧还原性能进行了测试。研究表明该催化材料在碱性溶液中的氧还原反应以四电子为主。
[Abstract]:Energy is the essential material foundation for the existence and development of human society. With the development of society, energy is decreasing day by day, and at the same time, it will lead to various environmental problems, which will inevitably hinder the development of human society and economy. It's very necessary to find new energy around the 3EW economy. Fuel cells have high energy density, low pollution, easy charging, simple structure, fast start at low temperatures, and the energy conversion process doesn't have to go through the Carnot cycle. A device that converts chemical energy directly to electrical energy, which is in line with green energy conditions. At present, Pt and PtM/C catalysts are widely used in various electrocatalytic reactions in fuel cells: alcohols. Anodic oxidation of similar fuel cells; hydrogen evolution in hydrogen fuel cells and hydrogen evolution reactions to produce hydrogen; and cathodic oxygen reduction ORR for fuel cells, etc. However, the world's Pt reserves are limited and expensive. The intermediate product CO in methanol oxidation reaction of Pt catalyst in methanol fuel cell is easy to be poisoned, and in the cathode of fuel cell, the "cross boundary reaction" is easy to occur when the anode is methanol, and the catalyst is deactivated. It is very difficult to develop Pt fuel cells on a large scale. Therefore, it is very important to explore the preparation of new non-platinum electrocatalysts. The development of new non-precious metal catalysts has become one of the long-term research topics in the development of fuel cells. In the absence of organic templates, the Beta molecular sieve (Beta) synthesized by tetraethyl ammonium hydroxide (TEAOH) was used as seed to induce the preparation of aluminum-rich Beta molecular sieve, and the Ni-Beta molecular sieve was prepared by ion exchange. By cyclic voltammetry and chronoamperometric method, the electrocatalytic activity of Ni-Beta-SDS electrode for methanol oxidation in alkaline solution is obviously higher than that of traditional Ni-Beta-TEA. Secondly, nickel cobaltate (NiCo2O4) with large surface area and multilevel pores was prepared by template free hydrothermal method. By cyclic voltammetry and chronoamperometry, The electrocatalytic activity of NiCo2O4 to MOR in alkaline solution is obviously higher than that of nickel oxide (Nio) and cobalt trioxide (Co _ 3O _ 4). Thirdly, nanosheet like molybdenum disulfide (MoS _ 2) was prepared by adding ammonium fluoride (NH _ 4F). The hydrogen evolution reaction was carried out in sulfuric acid solution. The results showed that the nanosheet like MoS2 was exposed to more active sites because of its thin film. The bulk MoS2 prepared without adding NH4F has better electrocatalytic activity. Finally, the mixture of polyhexamethylguanidine (PHMB) and graphene oxide (GOO) was oxidized at high temperature. The nitrogen-doped graphene N-Graphene has been prepared and its oxygen reduction properties have been tested in alkaline solution. The results show that the oxygen reduction reaction of the catalyst in alkaline solution is mainly composed of four electrons.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：O643.36;TM911.4

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