INTERNATIONAL COLLABORATION IN CHEMISTRY: Local structures of heteroatom environments and their effects on the reactivities of alumino-and borosilicates

在这个项目中，由化学系实验物理化学计划资助，国际科学与工程办公室支持，来自加州大学圣巴巴拉分校的ChMelka教授和他的法国合作者来自Orléans的National de la Recherche Science Labatoire de Conditions Extems et Matériaux，试图了解和控制高活性和高选择性的含杂原子的多孔硅酸盐和二氧化硅催化剂的分子起源，旨在提高化学过程的能源效率。这两个小组在催化剂合成、表征和光谱方法开发方面拥有互补的专业知识。该项目的主要目标是：(I)开发和应用最先进的固体核磁共振(NMR)光谱方法，以确定纳米多孔硅酸盐和二氧化硅材料中具有催化作用的重要铝和硼杂原子部分及其附近的局部组成和结构；(Ii)利用所获得的见解来设计和控制多孔硅酸盐和二氧化硅骨架中的杂原子环境，以改善其宏观吸附和反应性能；以及(Iii)教育和培训学生，使他们对核磁共振波谱的最新方法以及新催化材料的合成、表征和性能有坚实的基础了解。当地的组成和结构特征，特别是骨架铝和硼中心的组成和结构特征非常重要，因为它们对许多催化材料的宏观吸附和反应性能具有关键影响，例如硅酸铝沸石，这些材料几乎负责目前世界上所有的汽油生产。尽管它们在技术上很重要，但在分子水平上对它们的活动来源仍然知之甚少，主要是因为对Al和B活性部位的当地环境了解不足。从固体核磁共振研究中获得的见解将与催化材料的宏观物理化学性质(如酸性、反应性、吸附)相关联，以获得对其复杂行为的新的分子水平的理解。该项目的广泛影响包括展示新的通用方法，用于测量、理解、设计和改进说明不同类别催化剂的局部组成和结构特征。对这些领域的学生进行培训在国内和国际上都很重要，并将积极促进代表性不足群体的学生参与。美国和法国合作伙伴之间的合作和互补努力将为学生提供跨文化和跨学科的研究和教育机会，这些机会将广泛转移。预计从拟议项目中获得的见解将使学生和更广泛的科学界能够开发旨在提高工艺和设备能效的下一代材料。

In this project, funded by the Experimental Physical Chemistry Program of the Division of Chemistry with support from the Office of International Science & Engineering, Professor Chmelka from University of California, Santa Barbara and his French collaborators from the Centre National de la Recherche Scientifique Laboratoire de Conditions Extrêmes et Matériaux in Orléans, seek to understand and control the molecular origins of the high activities and high selectivities of heteroatom-containing porous silicate and silica catalysts aimed at improving the energy efficiencies of chemical processes. The two groups have complementary expertises in catalyst synthesis, characterization, and spectroscopy method development. The main objectives of the project are:(i) to develop and apply new state-of-the-art methods of solid-state nuclear magnetic resonance (NMR) spectroscopy to establish the local compositions and structures at and near catalytically important aluminum and boron heteroatom moieties in nanoporous silicate and silica materials;(ii) to use the resulting insights to design and control heteroatom environments in porous silicate and silica frameworks to improve their macroscopic adsorption and reaction properties; and(iii) to educate and train students to provide strong fundamental understanding of state-of-the-art methods of NMR spectroscopy and syntheses, characterization, and properties of new catalytic materials.Local compositional and structural features, especially of framework aluminum and boron sites, are important, because they crucially influence the macroscopic adsorption and reaction properties of many catalytic materials, such as aluminosilicate zeolites that are responsible for nearly all of the world's current gasoline production. Despite their technological importance, much remains unknown at a molecular level about the origins of their activities, principally because of insufficient knowledge about the local environments at the Al and B active sites. Insights gained from solid-state NMR investigations will be correlated with macroscopic physicochemical (e.g., acidity, reactivity, adsorption) properties of the catalytic materials to obtain new molecular-level understanding of their complicated behaviors.Broader impacts of the project include the demonstration of new and general approaches for the measurement, understanding, design, and improvement of the local compositional and structural features that account for the reactivities of diverse classes of catalysts. Training of students in these areas is important, both nationally and internationally, and participation by students from underrepresented groups will be actively promoted. The collaborative and complementary efforts between the U.S. and French partners will provide cross-cultural and interdisciplinary research and education opportunities for students that will be broadly transferrable. It is expected that the insights gained from the proposed project will enable students and the broader scientific community to develop next-generation materials aimed at improving the energy-efficiency of processes and devices.