GOALI/FRG: Structural Properties of Alumina and Adsorbed Metal Particles

GOALI/FRG：氧化铝和吸附金属颗粒的结构特性

• 批准号: 0111841
• 负责人: Sergey Rashkeev
• 金额: $ 39.78万
• 依托单位: Vanderbilt University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0111841&HistoricalAwards=false
• 关键词: GOALI; FRG; Structural; Properties; Alumina

The focus of the proposal is to pursue fundamental understanding of structural transformations in materials that occur in applications and device methods to control them so that they can be either averted or enhanced, as needed by industry. The specific problem of interest is the stabilization of g-alumina that is widely used as a catalyst support and as a catalyst. At high temperatures, g-alumina, which is porous, converts to a-alumina, which is not porous, and catalytic activity stops. Empirically, it has been found that the addition of 3.5-5% lanthanum stabilizes g-alumina. In a laboratory process developed by one of the PIs, it has been found that stabilization can be achieved with only 0.3-0.5% La, but the process is not scalable for manufacturing (La is very expensive). The proposed research will use a combination of atomic-resolution Z-contrast microscopy and electron-energy-loss spectroscopy and first-principles theoretical modeling to understand the atomic-scale processes that underlie the phase transformation and the stabilization with different impurities. A second problem will be the interaction of catalytic particles with the alumina substrate in catalytic systems. The PIs at two universities, a national lab, and an industrial lab have prior expertise and collaborative synergy on similar projects in the past and also propose to develop a parallel educational program. %%%The proposed research will seek to understand the atomic-scale processes that underlie a phenomenon that has proved to be quite costly for industry: the material known as g-alumina is porous and is used as a substrate in catalytic systems. At high temperatures, it undergoes a transformation to a different phase known as a-alumina (different atomic arrangements in the crystal), which is not porous. Catalytic activity stops. Addition of 3-5% of the rather expensive element lanthanum stabilizes g-alumina. One of the PI's developed an alternative process that produces stable g-alumina with only 0.3-0.5% La, but the process cannot be scaled for manufacturing. The PIs have an assembly of unique experimental and theoretical tools and have demonstrated synergistic collaboration in the past. They will be able to determine the atomic scale processes that are responsible for the transformation and the stabilization by impurities and develop alternative approaches with either La or other impurities that will be efficient and cost-effective. In addition, they propose to study related interactions between catalytic metal particles on alumina substrates. Finally, they propose an educational program that will enable students to participate in research done at a national lab and an industrial lab.

该提案的重点是追求对应用中发生的材料结构转变的基本理解和控制它们的设备方法，以便根据行业需要避免或增强它们。感兴趣的具体问题是广泛用作催化剂载体和催化剂的g-氧化铝的稳定化。在高温下，多孔的g-氧化铝转化为非多孔的a-氧化铝，催化活性停止。根据经验，已经发现添加3.5-5%的镧使g-氧化铝稳定。在一个由PI开发的实验室工艺中，已经发现仅用0.3-0.5%的La就可以实现稳定，但是该工艺对于制造来说是不可扩展的（La非常昂贵）。拟议的研究将使用原子分辨率Z对比显微镜和电子能量损失光谱学以及第一性原理理论建模的组合，以了解相变和不同杂质稳定化的原子尺度过程。第二个问题是催化体系中催化颗粒与氧化铝基质的相互作用。两所大学、一个国家实验室和一个工业实验室的PI在过去的类似项目中具有先前的专业知识和协作协同作用，并提议开发一个平行的教育计划。拟议的研究将试图了解原子尺度的过程，这种过程是一种现象的基础，这种现象已被证明对工业来说是相当昂贵的：被称为g-氧化铝的材料是多孔的，被用作催化系统中的基质。在高温下，它经历了一个不同的相称为α-氧化铝（晶体中不同的原子排列），这是不是多孔的转变。催化活性停止。添加3-5%的相当昂贵的元素镧使g-氧化铝稳定。其中一个PI开发了一种替代工艺，该工艺生产仅含0.3-0.5% La的稳定g-氧化铝，但该工艺无法按比例生产。PI拥有独特的实验和理论工具，并在过去表现出协同合作。他们将能够确定负责杂质转化和稳定的原子尺度过程，并开发具有La或其他杂质的替代方法，这些方法将是有效和具有成本效益的。此外，他们建议研究氧化铝基材上催化金属颗粒之间的相关相互作用。最后，他们提出了一个教育计划，使学生能够参与在国家实验室和工业实验室进行的研究。