贵金属纳米颗粒阳极电催化剂性能调控研究

发布时间：2018-03-14 18:33

本文选题：电催化　切入点：脱合金化　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：质子交换膜燃料电池(PEMFC)是二十一世纪重要能源,新型能源燃料电池的特点包括比能量高、启动迅速、环境友好、方便携带等,此类移动电源具有广阔的发展前景。贵金属颗粒是当前燃料电池方面普遍使用的催化剂,以铂,钯贵金属为主。而贵金属具有价格昂贵、资源有限、易发生毒化等特点,致使燃料电池的商业化发展较为迟缓。为了降低Pt、Pd的含量,提高其利用率,阐明催化剂贵金属的含量和粒径对催化剂的影响规律,进一步提高其电催化性能,是值得深入研究的科学课题,也是解决目前Pt基催化剂大规模商业化发展的关键之一。本文通过改善负载物,载体和添加物方式研究其对催化剂的电催化活性影响,意义在于探索出高性能低成本的燃料电池阳极催化剂,为这一绿色新能源技术未来实现商业化提供更翔实的数据和理论依据。通过三种方式的调整合成贵金属阳极催化剂,并探究其对有机小分子电催化性能的作用规律。主要研究分为以下三个部分:(1)通过液相还原法,制备Pd基催化剂,其中碳纳米管为载体,控制Pd、Ag原子比为1:1(研究已表明,此种情况下催化性能最佳),通过添加不同含量的Cu元素,探讨其催化剂性能提升的机理,研究系列Pd基催化剂在甲醇、乙醇和甲酸溶液中的电催化活性,结果表明Pd25Ag25Cu50/CNTs催化剂在甲醇、乙醇和甲酸氧化过程中展示出最佳的电催化活性,相比其它催化剂,稳定性也达到最高。(2)引用新型载体,简易Cu_3P-C复合载体策略来提高铂纳米颗粒对甲醇、乙醇、乙二醇和甲酸的电催化性能,控制Cu_3P与C的比例,探究发现当Cu_3P与C的质量比为1:1时,Pt/C-Cu_3P50%催化剂的电催化性能达到最高,说明复合载体的引入使Pt催化剂的催化活性得到提高。(3)引用添加物Fe_2P,探究Fe_2P不同比例含量下对Pt催化剂的电催化性能影响,其中Fe_2P含量较少且颗粒较小,区别于Cu_3P载体作用,分析其磷化物在较低含量下对甲酸、甲醇和乙醇的电催化活性影响。目前,磷化物作为新型材料,对燃料电池催化剂的电催化活性具有明显的增强作用。结果发现,添加物Fe_2P含量5%时达到合适的添加比例,此时Pt催化剂在甲醇,乙醇和甲酸有机小分子氧化过程中具有最佳的催化性能。
[Abstract]:Proton exchange membrane fuel cell (PEMFC) is an important energy source in 21th century. The characteristics of new energy fuel cell include high specific energy, quick start-up, friendly environment, easy to carry and so on. This kind of mobile power supply has broad development prospects. Precious metal particles are widely used catalysts in fuel cells at present, mainly platinum and palladium precious metals, while precious metals have the characteristics of high price, limited resources, easy to poison and so on. The commercial development of fuel cell is slow. In order to reduce the content of PtPd, improve the utilization rate, clarify the influence of the content and particle size of noble metal on the catalyst, and further improve its electrocatalytic performance. It is a scientific subject worthy of further study, and is also one of the keys to solve the large-scale commercial development of Pt-based catalysts. In this paper, the effects of Pt-based catalysts on their electrocatalytic activity are studied by improving the methods of support, support and additives. The significance lies in exploring the high performance and low cost anode catalyst for fuel cell, which will provide more detailed data and theoretical basis for the commercialization of this green new energy technology in the future. The PD based catalyst was prepared by liquid-phase reduction method, in which carbon nanotubes were used as the carrier, and the atomic ratio of PD / Ag was controlled to 1: 1. In this case, the best catalytic activity is obtained. The mechanism of improving the catalytic performance of the catalyst is discussed by adding different contents of Cu, and the electrocatalytic activity of a series of PD based catalysts in methanol, ethanol and formic acid solution is studied. The results showed that the Pd25Ag25Cu50/CNTs catalyst exhibited the best electrocatalytic activity in the oxidation of methanol, ethanol and formic acid, and the stability of the catalyst was the highest compared with other catalysts. The simple Cu_3P-C composite support strategy was used to improve the electrocatalytic performance of platinum nanoparticles for methanol, ethanol, ethylene glycol and formic acid, and to control the ratio of Cu_3P to C, it was found that when the mass ratio of Cu_3P to C was 1: 1, the electrocatalytic performance of the catalyst Pt- / C-C / Cu3P50% was the highest. It shows that the introduction of composite support can improve the catalytic activity of Pt catalyst. (3) the addition Fe2P is used to study the effect of Fe_2P on the electrocatalytic performance of Pt catalyst with different content of Fe_2P, in which the content of Fe_2P is less and the particle is smaller, which is different from the function of Cu_3P carrier. The effects of phosphates on the electrocatalytic activity of formic acid, methanol and ethanol in low content were analyzed. At present, as a new type of material, phosphates can enhance the electrocatalytic activity of fuel cell catalysts. When the content of Fe_2P is 5, the Pt catalyst has the best catalytic performance in the oxidation of methanol, ethanol and formic acid organic small molecule.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TM911.4

【参考文献】