论文总字数:21447字
摘 要
直接甲酸燃料电池(DFAFC)具有无毒害、不易燃、高能量密度的优点和广阔的应用前景。阳极催化剂的研究表明,Pd基催化剂虽然电催化氧化甲酸性能高于Pt基,但是Pd催化剂的稳定性差。本论文开展了金属氧化物TiO2纳米纤维作为DFAFC阳极Pt基催化剂载体材料的研究,提高对甲酸的电催化氧化活性。通过静电纺丝技术和还原浸渍法结合,制备了Pt/TiO2纳米纤维催化剂, 进行了扫描电镜(SEM)、X射线衍射分析 (XRD) 、X射线能谱(EDS) 和透射电镜(TEM)等表征,对样品的形貌、晶型、结构等进行了一系列分析。 结果表明, TiO2纳米纤维是由锐钛矿和金红石组成的混晶,Pt纳米颗粒均匀地负载到TiO2表面,平均粒径为4.0 nm,Pt质量分数约为20 %。 采用三电极体系进行了循环伏安和CO浮出电化学分析,研究了样品对甲酸的电催化氧化活性和抗中毒能力, 结果表明, 与负载相同质量分数Pt的商业Pt/C催化剂相比较, Pt/TiO2表现出了更强的催化活性和抗CO中毒性能。
关键词:直接甲酸燃料电池;阳极催化剂;二氧化钛;纳米材料;甲酸催化氧化
Preparation of Pt/TiO2 nano-fiber and its electrocatalytic oxidation of formic acid
Abstract
Direct formic acid fuel cells have many characteristics such as non-toxic, non-flammable, safe, high energy density. which have a very good application prospects. Previous research results show that the electrocatalytic activity of the Pd anode catalyst for the oxidation of formic acid is better than that of the Pt catalyst. However, its electrocatalytic stability is so poor. In this thesis, in order to improve the catalytic oxidation activity, a study on the metal oxide TiO2 nano-fiber as DFAFC anode Pt based catalyst support material has been carried out. Pt/TiO2 nano-fibers catalyst was prepared by combining electrospinning technique with reduction impregnation method. The composition, morphologies and structures of samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy disperse spectroscopy (EDS). The results show that the crystal phase of TiO2 nano-fibers is composed of anatase and rutile. Pt nanoparticles uniformly distribute on the surface of TiO2 nano-fibers and the average size is 4.0 nm. The mass fraction of Pt in Pt/TiO2 nano-fibers catalyst is about 20%. The electrocatalytic activity of the samples for formic acid was measured by cyclic voltammetry and chronoamperometry with a three-electrode system in an acidic solution. Compared with the commercial Pt/C catalyst containing the same quality percentage of Pt nanoparticles, Pt/TiO2 nanofibers catalyst for formic acid exhibits higher catalytic oxidation activity and stability.
Key words: direct formic acid fuel cell; anode catalyst; titanium dioxide; nano materials; formic acid catalytic oxidation
目录
摘要 2
Abstract 3
第一章 绪论 6
1.1 引言 6
1.2 燃料电池概述 6
1.2.1 燃料电池的工作原理 7
1.2.2 燃料电池的特点 7
1.2.3 燃料电池的分类 8
1.3 直接甲酸燃料电池(DFAFC)概述 8
1.3.1 直接甲酸燃料电池发展概况 8
1.3.2 直接甲酸燃料电池的基本结构 9
1.3.3 直接甲酸燃料电池的工作原理 10
1.4 直接甲酸燃料电池中甲酸的电氧化机理 10
1.4.1 直接途径 10
1.4.2 间接途径 11
1.5 DFAFC中阳极催化剂研究概况 12
1.5.1阳极催化剂分类 12
1.5.2 阳极催化剂载体研究 13
1.5.3 Pt基阳极催化剂的制备方法 14
1.6 TiO2简介 15
1.6.1 TiO2纳米材料的制备方法 15
1.7 选题依据及研究意义 16
第二章 实验部分 18
2.1 试剂与仪器 18
2.2 20%(w) Pt/TiO2电催化剂的制备 18
2.3 电化学测试 19
第三章 结果与讨论 20
3.1催化剂的结构和形貌 20
第四章 结论 26
致谢 27
参考文献 28
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