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

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，以及控制它们的设备方法，以便根据工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-氧化铝的稳定问题。在高温下，多孔的g-氧化铝转化为不多孔的a-氧化铝，催化活性停止。经验表明，添加3.5 ~ 5%镧对g-氧化铝有稳定作用。在其中一家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，但该工艺无法用于制造（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以及第一性原理理论模型的组合来理解原子尺度的过程，这些过程是相变和不同杂质稳定的基础。第二个问题将是催化系统中催化颗粒与氧化铝衬底的相互作用。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验的专业知识和协作协同作用，并且还建议开发平行的教育计划。提议的研究将寻求理解一种现象背后的原子尺度过程，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，被用作催化系统的基板。在高温下，它会转变成一种不同的相，称为a-氧化铝（晶体中不同的原子排列），这种相是不多孔的。催化活性停止。添加3-5%相当昂贵的元素镧可以稳定g-氧化铝。其中一个PI开发了一种替代工艺，可以生产出只含0.3-0.5% La的稳定g-氧化铝，但该工艺无法规模化生产。pi拥有独特的实验和理论工具，并在过去展示了协同合作。他们将能够确定负责杂质转化和稳定的原子尺度过程，并开发出使用La或其他杂质的替代方法，这将是高效和经济的。此外，他们建议研究氧化铝基板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，使学生能够参与国家实验室和工业实验室所做的研究。

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.