SusChEM: Structural and Mechanistic Insights into the Enhanced Hydrogen Sorption Properties of Metal Hydride Nanoparticles Made via Solution Reactions

SusChEM：通过溶液反应制备的金属氢化物纳米颗粒增强氢吸附性能的结构和机理见解

• 批准号: 1508790
• 负责人: Amy Prieto
• 金额: $ 42.6万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1508790&HistoricalAwards=false
• 关键词: SusChEM; Structural; Mechanistic; Insights; into

Hydrogen is an ideal fuel for vehicles and other portable applications because it burns cleanly in air and the only byproduct is water. It also has a very high energy density, almost three times higher than gasoline. The main challenges to using hydrogen as a fuel, however, are its clean production and storage. Storing hydrogen as a gas requires large cylinders, and storing it as a liquid requires high pressures and very low temperatures. Both methods also present safety challenges. Dr. Prieto is exploring the use of solid compounds as storage materials for hydrogen. This approach offers small storage volumes at reasonable pressures. Light metal hydrides, such as magnesium metal, can store a lot of hydrogen per unit mass, but the drawbacks are that putting the hydrogen into magnesium requires high temperatures and pressures, and removing the hydrogen requires high temperatures and low pressures. Both processes are very slow. Dr. Prieto and her students have designed a method of making very small particles of magnesium that display much faster rates for storing hydrogen. The goal of her work is to determine whether the addition of small amounts of other metals to the surface of the magnesium can further increase the rates of adding or removing the hydrogen from the metal particles. She uses techniques such as X-ray diffraction, thermal analysis, solid state nuclear magnetic resonance, and X-ray absorption experiments to help model the rates of the hydrogenation reactions and to provide data that aid in developing kinetic models to describe these reactions. Dr. Prieto involves students ranging from high school to graduate levels in her research, and the practical applications of this work serve as a useful recruiting tool to attract talented students and train them in research aimed at improving energy sustainability. Prof. Prieto communicates her knowledge of hydrogen storage and energy sustainability to the general public through her role as a board member of the Colorado Clean Energy Cluster, which is directly impacting policy in Colorado for economic development and projects related to clean energy production, storage, and transportation. This project is used as an example of basic research that can be easily linked to an application interesting to a wide audience, that of clean energy production and storage. Hydrogen is an ideal fuel for portable applications because it burns cleanly in air to produce water, and it has a very high energy density. Magnesium (Mg), doped Mg, and Mg alloys are promising materials for hydrogen storage due to their high theoretical hydrogen storage capacities (e.g. 7.6 weight% for MgH2). However, bulk Mg is less than ideal as a hydrogen storage material due to the slow kinetics and high temperatures required for hydrogen absorption and desorption. Dr. Prieto is synthesizing nanoparticles of hydrogen storage materials in which the reduced size results in significantly enhanced kinetics for hydrogen storage. She is determining the relative roles of kinetics and thermodynamics on the hydrogen sorption and desorption of these particles, particularly upon addition of small amounts of transition metals to the surface. Although faster hydrogenation rates have been observed for nanoscale metal hydrides, very little is known about the roles of increased surface area versus impurities and defects. The targets Dr. Prieto is studying are earth abundant elements that are light and store large amounts of hydrogen, albeit sluggishly in the bulk. With control over the particle size and additive type and position, she can dramatically increase the slow hydrogenation rates observed in the bulk and, ultimately, be able to lower the temperature required for hydrogenation of these materials. This research results in recruiting and retaining a talented, diverse group of students.

氢是汽车和其他便携式应用的理想燃料，因为它在空气中燃烧干净，唯一的副产品是水。它还具有非常高的能量密度，几乎是汽油的三倍。然而，使用氢气作为燃料的主要挑战是其清洁的生产和储存。将氢气储存为气体需要大钢瓶，将其储存为液体需要高压和非常低的温度。这两种方法也都带来了安全挑战。普利托博士正在探索使用固体化合物作为氢的储存材料。这种方法以合理的压力提供较小的存储容量。轻金属氢化物，如金属镁，每单位质量可以储存大量氢气，但缺点是，将氢气放入镁中需要高温和压力，而去除氢气需要高温和低压。这两个过程都非常缓慢。普利托博士和她的学生设计了一种制造非常小的镁颗粒的方法，这种颗粒储存氢气的速度要快得多。她的工作目标是确定在镁表面添加少量其他金属是否可以进一步提高向金属颗粒添加氢或从金属颗粒中去除氢的速度。她使用X射线衍射、热分析、固体核磁共振和X射线吸收实验等技术来帮助模拟氢化反应的速率，并提供有助于开发描述这些反应的动力学模型的数据。普利托博士的研究涉及从高中到研究生的学生，这项工作的实际应用是一个有用的招聘工具，可以吸引有才华的学生，并在旨在提高能源可持续性的研究中对他们进行培训。作为科罗拉多州清洁能源集群的董事会成员，Prieto教授通过她作为科罗拉多州清洁能源集群董事会成员的角色向公众传播她关于氢气储存和能源可持续性的知识，该集群直接影响着科罗拉多州的经济发展政策以及与清洁能源生产、储存和运输相关的项目。这个项目被用作基础研究的例子，可以很容易地与广大受众感兴趣的应用相联系，即清洁能源生产和储存。氢是便携式应用的理想燃料，因为它在空气中清洁燃烧产生水，而且它具有非常高的能量密度。镁、掺杂镁和镁合金具有较高的理论储氢容量(例如镁含量为7.6%)，是一种很有前途的储氢材料。然而，块体镁作为储氢材料并不理想，因为吸氢和放氢需要缓慢的动力学和较高的温度。Prieto博士正在合成储氢材料的纳米颗粒，这种纳米颗粒尺寸的减小导致了储氢动力学的显著增强。她正在确定动力学和热力学在这些颗粒的氢吸附和脱附方面的相对作用，特别是在向表面添加少量过渡金属时。虽然纳米级金属氢化物的氢化速度更快，但人们对增加表面积对杂质和缺陷的作用知之甚少。普利托博士正在研究的目标是地球上丰富的元素，这些元素很轻，可以储存大量的氢，尽管体积很小。通过控制颗粒大小和添加剂的类型和位置，她可以显著提高在散装材料中观察到的缓慢加氢速度，并最终能够降低这些材料加氢所需的温度。这项研究的结果是招收和留住一批有才华的、多样化的学生。