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摘要燃料电池作为一种清洁，高效的能源正受到越来越多的关注。铂基电催化剂在燃料电池上作用有目共睹，但铂纳米颗粒在形核生长时，受到生长环境的温度，压力，反应环境等原因导致形成晶粒直径大，比表面积小，制约了催化效率。针对以上问题，本研究对炭材料搭载钯催化剂的负载方法进行了研究，比较了不同负载方式（浸渍法、NABH还原法与乙二醇还原法）和不同载体（VCX72与碳纳米笼）对铂沉积的影响：乙二醇还原法相对本研究中其它发放有更好的沉积效果，因为乙二醇还原时，铂还原速率慢于浸渍法，便于控制使得到的铂颗粒粒径较小，提高了铂的比表面积。在不同载体对铂沉积的影响比较中，碳纳米笼优于VCX72，由于碳纳米笼有更大的比表面积，在相同负载量的情况下，铂在碳纳米笼的表面有更多的形核点，同时更大的比表面积也有利于铂颗粒在碳纳米笼的表面分布的更加分散，提高负载效果。8747
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关键词：碳纳米笼；铂纳米颗粒；比表面积
Abstract
Fuel cells regarded as a clean and efficient energy, is drawn more and more attention. Obviously, platinum electro-catalyst is useful in fuel cells. However, nucleation growth of platinum nanoparticles is deeply influenced by temperature, pressure, environment and so on, leading to forming large Pt nanoparticles and low specific surface area, which reduces the catalysis. Here, the methods for loading Pt nanoparticles on C support have been investigated to release those problems. For comparison, three loading methods (reduction by NaBH, ethylene glycol and macerating) and two different supports (VCX-72 and carbon nanocages) are involved. As a result, Pt deposition by ethylene glycol method is more effective route than other ones for Pt loading, because this method decreases reduction rate of Pt and a controllable reduction processing leads to smaller sizes of Pt nanoparticles and high specific surface area as well. Compared with VCX-72, carbon nanocages perform better, as Pt support materials, due to their high specific surface area. When Pt loading amount is the same, there are more nucleation points for Pt deposition and high surface area also improve distribution of Pt nanoparticles on the nanocage surface, leading to improvement of Pt Loading.
Keyword: Carbon nanocages; Platinum nanoparticles; Specific surface area
目 录
摘 要 1
1 绪论 2
1.1 燃料电池的综述 2
1.2 直接甲醇燃料电池的发展背景 3
1.3 课题的研究意义和内容 6
2 实验部分 8
2.1 实验设备以及原料 8
2.2 实验过程 9
2.2.1多孔壁碳纳米笼的制备 9
2.2.2 铂/碳催化剂的制备 10
2.2.3 样品表征 11
3 结果与讨论 13
3.1 X射线衍射数据处理 13
3.1.1 VCX-72，乙二醇环境下液相还原 13
3.1.2 VCX-72，硼氢化钠环境下液相还原 14
3.1.3 多孔碳纳米笼，乙二醇环境下液相还原 15
3.1.4 浸渍法还原 16
3.2 X射线衍射数据比较 18
3.2.1 乙二醇-硼氢化钠反应环境下的数据比较 18
3.2.2 浸渍法和液相还原法的数据比较 19
3.2.4 X射线衍射小结 21
3.3 TEM透射电镜图像分析 22
3.3.1 多孔碳纳米笼 22
3.3.2 VCX-72乙二醇还原环境下负载铂纳米颗粒 23
3.3.3多孔碳纳米笼负载铂纳米颗粒 24
3.3.4 TEM透射电镜小结 25