SGER: Platinum Nanofibers as Fuel Cell Electrodes

技术：由于铂（Pt）是一种有效的催化剂，但也是一种昂贵的金属，因此需要一种具有大表面体积比的结构来最大限度地减少其使用。所有可用的技术都需要支撑物和支撑物之间良好的粘附性，例如碳和铂纳米颗粒。这种粘附性通常不好，这是燃料电池等应用中面临的耐久性问题的主要来源。一个独立的纯铂网络也将是许多其他化学应用和工艺的一个受欢迎的成分，它的发展是这个高风险、高回报、具有变革性的SGER项目的重点。通过使用类似Magnus绿盐的铂链化合物，PI可以生产出适合燃料电池电极的铂纳米线网络。然而，电线的尺寸较大。PI会将尺寸减小到10纳米。这种有或没有支撑的纯Pt独立电极应该比目前可用的分散在多孔碳支撑中的Pt纳米粒子的电极更有效。此外，PI还可以通过静电纺丝生产Pt和Pt/Ni合金纳米线。直径约20纳米。PI的目标是缩小直径，从而进一步减少铂的使用。这些导线可以单独使用，也可以与碳纤维混合制成电极。这项工作的高回报和变革性特征是，没有迁移的纳米颗粒，电线将更加稳定，从而产生的燃料电池将更加耐用。这种设计也将更加稳定，因为没有纳米颗粒可以迁移和聚集。虽然回报巨大，但有三个方面的风险必须加以管理和克服。一个是三相接触点。PI必须确保有足够的三相（气体、电解质和电极）接触点，以实现高效的电池操作。二是集聚机制。它必须是小颗粒的迁移和聚并，才能有纳米线的好处。第三是纳米线的电阻率。为此，PI计划将铂镀在支撑的微线上。非技术：金属通常以大块固体形式存在，包括细粉末、线和薄膜。因此，用化学方法制备Pt纳米线网络是一个挑战。它既需要化学知识，也需要材料科学知识。需要化学来了解所涉及的反应，需要材料科学来了解微观结构是如何演变的。PI计划在SGER研究中结合这两个元素，为能源应用的燃料电池开发坚固高效的电极。这位PI拥有化学博士学位，但也有多年的材料研究经验。他的助手是一名有化学合成经验的化学工程研究生和一名有纳米线经验的材料科学研究生。对于研究生、本科生和高中生来说，燃料电池也是一个有吸引力的领域。PI会让他们参与进来，让他们意识到当前的能源问题。

TECHNICAL: Since platinum (Pt) is an effective catalyst but an expensive metal, a structure with a large surface-to-volume ratio is needed to minimize its use. All the available techniques require a support and a good adherence between the support such as carbon and nanoparticles of Pt. The adhesion is generally not good and this is a major source of the durability problem one faces in applications such as fuel cells. A free-standing pure Pt network would also be a welcome ingredient in many other chemical applications and processes, and its development is the focus of this high-risk, high payoff, and transofrmative SGER project. By using a Pt chain compound similar to Magnus green salt, PI can produce a nanowire network of Pt suitable for fuel cell electrodes. However, the size of wire is large. PI would reduce the size to 10 nm. This pure Pt free-standing electrode with or without a support should be more efficient than the ones so far available in which Pt nanoparticles are dispersed in a porous carbon support. In addition, PI can produce nanowires of Pt and Pt/Ni alloys by electro-spinning. The diameter is about 20 nm. PI would aim to get smaller diameters so as to further reduce the use of Pt. These wires can stand alone or mingle with carbon fibers to make electrodes. The high payoff, transformative characteristics of this work would be that without migrating nanoparticles, the wires would be more stable so the resulting fuel cells would be more durable. This design will also be more stable since there are no nanoparticles which could migrate and agglomerate. While the payoff is huge, there are three areas of risk that must be managed and overcome. One is the 3-phase contact points. PI would have to ensure that there are enough 3-phase (gas, electrolyte and electrode) contact points for efficient cell operation. The second is the mechanism of agglomeration. It must be the migration and coalescence of small particles in order to have the benefits of nanowires. The third is the resistivity of nanowires. For that PI plans to plate Pt onto the micro-wires of support. NON-TECHNICAL: Metals are usually in a bulk solid form including fine powders, wires and thin films. Hence it is a challenge to make nanowire network of Pt by chemical means. It requires both the knowledge in chemistry and in materials science. Chemistry is needed to understand the reactions involved and materials science to see how the microstructure was evolved. PI plans to combine these two elements in this SGER research towards the development of robust and efficient electrodes for fuel cells for energy applications. The PI has a doctorate in chemistry but also has many years experience in materials research. He is assisted with a graduate student in Chemical Engineering who has experience in chemical synthesis and another one in materials science who has experience in nanowires. Fuel cell is also an attractive area for graduate, undergraduate, and high school students. PI would involve them and make them aware of the current energy problems.