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纯铂金的替代燃料电池技术的承诺突破

2018-4-22 10:11| 发布者: dymodel| 查看: 214| 评论: 0|原作者: tz2009

摘要: 多金属纳米颗粒为燃料电池反应产生使用核心和铁钯铂壳(图片: Vismadeb Mazumder & Shouheng太阳,布朗大学) 为广泛采用的最明显的障碍 燃料电池 技术的成本和性能。虽然他们承诺在环境影响方面超过内燃发动机 ...


多金属纳米颗粒为燃料电池反应产生使用核心和铁钯铂壳(图片: Vismadeb Mazumder & Shouheng太阳,布朗大学)

为广泛采用的最明显的障碍 燃料电池 技术的成本和性能。虽然他们承诺在环境影响方面超过内燃发动机和电池的好处,但仍然在这些原因相当有限使用。在大多数燃料电池使用的最昂贵的要素之一,是铂金,但现在已开发出一种独特的核心和壳纳米粒子的使用大大减少铂,但执行更有效,持续在阴极结束时间比市售纯铂催化剂燃料电池的反应。
对氧还原反应,发生在燃料电池的阴极地方创建作为其唯一的废水和它的存在,多达40燃料电池的效率是百分之丢失。铂已就这方面的许多研究人员选择的反应催化剂,但它是昂贵的,反应的原因随着时间的推移它打破了。该核壳纳米粒子的研究人员开发的 布朗大学 和 橡树岭国家实验室 这些问题都解决了。
该小组建立了一个5纳米钯(Pd )的核心和包围了铁和铂( FePt合金)组成的外壳了。诀窍是在塑造一个外壳,将保留它的形状和需要最少量的铂金拉了一个有效的反应。车队创建分解铁pentacarbonyl和减少导致铂乙酰壳只有百分之三十,使用铂,铁,铂金壳。虽然研究人员说,他们希望能够使更薄的炮弹,并使用更少白金。
研究人员首次证实,他们能够不断生产出独特的核壳结构。在实验室测试中,钯/铁铂纳米粒子生成的12倍以上市售纯铂催化剂目前在同一催化剂的重量。输出还保持一致超过10,000次,至少10倍以上的商业模式,提供白金开始恶化后, 1000周期。
该小组在铁白金,在不同宽度从1至3纳米炮弹。在实验室测试中,发现了一组纳米壳的效果最佳。
“这是一个很好的示范,与核心和壳催化剂,可在半克数量容易在实验室中,他们是活跃,他们最后说,“布朗研究生, Vismadeb Mazumder 。 “下一个步骤是规模用于商业用途他们,我们有信心,我们就可以这样做。 “
Mazumder和Shouheng太阳,在布朗的化学教授,是研究为什么钯铂核心增加了铁的催化能力,但他们认为它是与之间的核心和壳金属电子转移。为此,他们正试图利用为核心的比化学更积极的金属钯,以确认在核壳安排的电子转移到它的重要性和催化剂的作用。

原文:
The multi-metallic nanoparticle created for fuel-cell reactions uses a palladium core and an iron-platinum shell (Image: Vismadeb Mazumder & Shouheng Sun, Brown University)

The most obvious obstacles for the widespread adoption of fuel cell technology are cost and performance. Although they promise benefits over internal combustion engines and batteries in terms of environmental impact, they are still fairly limited in use for these reasons. One of the most expensive elements used in most fuel cells is platinum, but now researchers have created a unique core and shell nanoparticle that uses far less platinum, yet performs more efficiently and lasts longer than commercially available pure-platinum catalysts at the cathode end of fuel cell reactions.
The oxygen reduction reaction that takes place at the fuel cell’s cathode creates water as its only waste and it is there that up to 40 percent of a fuel cell’s efficiency is lost. Platinum has been the catalyst of choice for this reaction for many researchers, but it is expensive, and the reaction causes it to break down over time. The core-shell nanoparticle developed by researchers at Brown University and Oak Ridge National Laboratory addresses both of these problems.
The team created a five-nanometer palladium (Pd) core and encircled it with a shell consisting of iron and platinum (FePt). The trick was in molding a shell that would retain its shape and require the smallest amount of platinum to pull off an efficient reaction. The team created the iron-platinum shell by decomposing iron pentacarbonyl and reducing platinum acetylacetonate to result in a shell that uses only 30 percent platinum. Although the researchers say they expect to be able to make thinner shells and use even less platinum.
The researchers demonstrated for the first time that they could consistently produce the unique core-shell structures. In laboratory tests, the palladium/iron-platinum nanoparticles generated 12 times more current than commercially available pure-platinum catalysts at the same catalyst weight. The output also remained consistent over 10,000 cycles, at least ten times longer than commercially available platinum models that begin to deteriorate after 1,000 cycles.
The team created iron-platinum shells that varied in width from one to three nanometers. In lab tests, the group found the one-nanometer shells performed best.
“This is a very good demonstration that catalysts with a core and a shell can be made readily in half-gram quantities in the lab, they’re active, and they last,” said Brown graduate student, Vismadeb Mazumder. “The next step is to scale them up for commercial use, and we are confident we’ll be able to do that.”
Mazumder and Shouheng Sun, professor of chemistry at Brown, are studying why the palladium core increases the catalytic abilities of iron platinum, although they think it has something to do with the transfer of electrons between the core and shell metals. To that end, they are trying to use a chemically more active metal than palladium as the core to confirm the transfer of electrons in the core-shell arrangement and its importance to the catalyst’s function.

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