Continuous and Scalable Manufacturing of Platinum-Nickel Nanocatalysts for Polymer Electrolyte Membrane Fuel Cells

具有可控形状的金属纳米晶体对于各种应用是必不可少的，包括能量转换、环境保护和化学/制药制造。尽管最近在其合成方面取得了进展，但在将纳米晶体从学术研究过渡到工业应用方面仍然存在重大差距，主要是由于缺乏在不影响质量的情况下以工业相关规模制造它们的能力。最近的演示表明，连续流液滴反应器提供了一个实用的平台，可扩展的和具有成本效益的生产具有均匀的尺寸和控制的形状的金属纳米晶体。基于液滴的平台提供了一种线性可扩展的技术，该技术可以在基本相同的条件下以小批量和大批量操作，分别用于方案优化和制造的目的。除了科学和技术进步，该奖项将有助于建立不同学科之间的联系，包括非制造，材料科学，催化，胶体科学和能源技术。它还在以下两个方面对社会产生直接影响：燃料电池纳米催化剂的制造，这是一项真正的零排放技术，对环境保护至关重要;通过让妇女、少数民族和其他代表性不足的群体参与到这个项目中来，促进高等教育的多样性。在与日产的合作者合作中，该团队的目标是开发一种新技术，用于八面体铂镍纳米晶体的可扩展制造。这种纳米晶体已经在间歇式反应器中产生，并表现出对氧还原的最高活性，这是聚合物电解质膜燃料电池（PEMFC）阴极上发生的关键反应。然而，由于批次间重现性差和合成之间不可避免的变化，已经证明获得足够量的均匀纳米晶体用于器件测试具有挑战性。通过该奖项，将根据动力学测量确定金属前体和还原剂的最佳组合，以确保还原不会过早发生，而是仅在液滴反应器通过保持在高温下的反应区时发生。还将开发类似的方案，用1-2个原子层厚的铂壳共形地涂覆铂镍八面体的表面，以大大提高其催化活性。这些催化剂将由日产的工程师进行测试，并评估其在由PEMFC驱动的车辆中的商业用途。这项研究将为未来部署基于可控形状纳米晶体的工业催化剂铺平道路。

Metal nanocrystals with controlled shapes are essential to a variety of applications, including energy conversion, environmental protection, and chemical/pharmaceutical manufacturing. Despite recent progress in their synthesis, there still exists a major gap in transitioning the nanocrystals from academic studies to industrial applications, primarily due to the lack of ability to manufacture them at an industrially relevant scale without compromising quality. Recent demonstrations indicate that continuous-flow droplet reactors offer a practical platform for the scalable and cost-effective production of metal nanocrystals with uniform sizes and controlled shapes. The droplet-based platform offers a linearly scalable technology that can be operated at both small and large quantities under essentially identical conditions for the purposes of protocol optimization and manufacturing, respectively. In addition to the scientific and technological advances, this award will help forge links between different disciplines that include nonmanufacturing, materials science, catalysis, colloidal science, and energy technology. It also has immediate impacts on the society in the following two aspects: manufacturing of nanocatalysts for fuel cells, a truly zero-emission technology critical to environmental protection; and promotion of diversity in higher education by engaging women, minorities, and other underrepresented groups into this project.In working with its collaborators at Nissan, the team aims to develop a new technology for the scalable manufacturing of octahedral platinum-nickel nanocrystals. Such bimetallic nanocrystals have been produced in batch reactors and demonstrated with the highest activity toward oxygen reduction, a key reaction occurring on the cathodes of polymer electrolyte membrane fuel cells (PEMFCs). However, due to the poor batch-to-batch reproducibility and inevitable variations between syntheses, it has proven challenging to obtain an adequate amount of uniform nanocrystals for device testing. Through this award, an optimal combination of metal precursors and reductant will be identified based on kinetic measurements to ensure that the reduction will not occur prematurely, and instead only when the droplet reactors pass through a reaction zone held at an elevated temperature. A similar protocol will also be developed to conformally coat the surfaces of platinum-nickel octahedra with platinum shells of 1-2 atomic layers thick to greatly enhance their catalytic activity. The catalysts will be tested by engineers at Nissan and evaluated for commercial use in vehicles powered by PEMFCs. This research will pave the way for future deployment of industrial catalysts based on nanocrystals with controlled shapes.